drawlayer.c

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/*
    This file is part of the Ansel project.
    Copyright (C) 2026 Aurélien PIERRE.
 
    Ansel is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    Ansel is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with Ansel.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#ifdef HAVE_CONFIG_H
#include "system/macros.h"
#include "common/module_versioning.h"
#include "common/logging.h"
#include "system/mem_alloc.h"
#include "system/openmp.h"
#include "system/target_clones.h"
#include "common/paths.h"
#include "common/hash.h"
#include "config.h"
#endif
#include "develop/masks_gui.h"
 
#include "widgets/bauhaus.h"
#include "common/colorspaces_inline_conversions.h"
#include "system/dtpthread.h"
#include "common/imagebuf.h"
#include "imageio/imageio_module.h"
#include "develop/iop_profile.h"
#include "common/opencl.h"
#include "common/conf.h"
#include "control/control.h"
#include "control/jobs.h"
#include "develop/dev_history.h"
#include "develop/develop.h"
#include "develop/imageop.h"
#include "develop/imageop_gui.h"
#include "develop/imageop_math.h"
#include "develop/masks.h"
#include "caches/pixelpipe_cache.h"
#include "pixel/interpolation.h"
#include "gui/color_picker_proxy.h"
#include "gui/application.h"
#include "develop/gui_throttle.h"
#include "iop/drawlayer/brush.h"
#include "iop/drawlayer/cache.h"
#include "iop/drawlayer/common.h"
#include "iop/drawlayer/coordinates.h"
#include "iop/drawlayer/io.h"
#include "iop/drawlayer/module.h"
#include "iop/drawlayer/paint.h"
#include "iop/drawlayer/runtime.h"
#include "iop/drawlayer/widgets.h"
#include "iop/drawlayer/worker.h"
#include "iop/iop_api.h"
 
#include <glib/gstdio.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <sched.h>
#include <stdlib.h>
#include <string.h>
#include "widgets/notebook.h"
#include "widgets/widget_style.h"
 
DT_MODULE_INTROSPECTION(1, dt_iop_drawlayer_params_t)
 
 
/*
 * drawlayer architecture summary
 * ------------------------------
 *
 * This module stores a painted premultiplied RGBA layer in a half-float TIFF sidecar.
 * The persistent layer lives in full image coordinates (raw-sized canvas, but in the
 * module's current pipeline geometry, not in raw sensor geometry). The GUI keeps:
 *
 * 1. a full-resolution half-float cache of the selected TIFF layer (`base_patch`),
 * 2. (legacy) a widget-sized ARGB preview overlay (`live_surface`) for immediate feedback,
 * 3. a worker thread that consumes stroke samples while the module has focus.
 *
 * The current stroke model is intentionally conservative:
 * - `distance` defines a spatial metronome for resampling the path independently of
 *   `mouse_moved` dispatch cadence.
 * - smoothing is applied only to the incoming raw cursor point before that resampling.
 * - the kept implementation uses a simple linear extrapolation from two anchor samples
 *   separated by one brush radius. Several "cleverer" variants were tried here
 *   (kernel caching, fixed-N smoothing windows, higher-order extrapolation, inertial
 *   direction filters), but they either benchmarked slower, introduced sampling
 *   dependence again, or created visible cusps/overshoot. Those attempts were removed
 *   and are documented locally near the code they affected.
 *
 * The guiding rule throughout this file is: keep the authoritative geometry in layer
 * space, and derive widget-space feedback from it, so GUI preview and pipeline output
 * cannot drift apart due to duplicated math.
 */
 
#ifdef HAVE_OPENCL
typedef struct dt_iop_drawlayer_global_data_t
{
  int kernel_premult_over;
} dt_iop_drawlayer_global_data_t;
#endif
 
typedef struct drawlayer_preview_background_t
{
  gboolean enabled;
  float value;
} drawlayer_preview_background_t;
 
typedef dt_drawlayer_runtime_request_t drawlayer_runtime_request_t;
typedef dt_drawlayer_runtime_context_t drawlayer_runtime_host_context_t;
 
#define _commit_dabs dt_drawlayer_commit_dabs
#define _flush_layer_cache dt_drawlayer_flush_layer_cache
#define _sync_widget_cache dt_drawlayer_sync_widget_cache
#define _set_drawlayer_pipeline_realtime_mode dt_drawlayer_set_pipeline_realtime_mode
#define _ensure_layer_cache dt_drawlayer_ensure_layer_cache
#define _release_all_base_patch_extra_refs dt_drawlayer_release_all_base_patch_extra_refs
#define _drawlayer_wait_for_rasterization_modal dt_drawlayer_wait_for_rasterization_modal
#define _current_live_padding dt_drawlayer_current_live_padding
#define _layer_to_widget_coords dt_drawlayer_layer_to_widget_coords
#define _touch_stroke_commit_hash dt_drawlayer_touch_stroke_commit_hash
#define _drawlayer_runtime_collect_inputs NULL
#define _drawlayer_runtime_perform_action NULL
 
gboolean dt_drawlayer_commit_dabs(dt_iop_module_t *self, gboolean record_history);
gboolean dt_drawlayer_flush_layer_cache(dt_iop_module_t *self);
static void _sync_mode_sensitive_widgets(dt_iop_module_t *self);
static void _refresh_layer_widgets(dt_iop_module_t *self);
static void _sync_layer_controls(dt_iop_module_t *self);
static void _sanitize_requested_layer_name(const char *requested, char *name, size_t name_size);
static gboolean _prompt_layer_name_dialog(const char *title, const char *message, const char *initial_name,
                                          char *name, size_t name_size);
gboolean dt_drawlayer_sync_widget_cache(dt_iop_module_t *self);
void dt_drawlayer_set_pipeline_realtime_mode(dt_iop_module_t *self, gboolean state);
static gboolean _background_layer_job_done_idle(gpointer user_data);
static dt_drawlayer_runtime_result_t _update_gui_runtime_manager(dt_iop_module_t *self,
                                                                 dt_iop_drawlayer_gui_data_t *g,
                                                                 dt_drawlayer_runtime_event_t event,
                                                                 gboolean flush_pending);
static void _sync_cached_brush_colors(dt_iop_module_t *self, const float display_rgb[3]);
 
typedef struct drawlayer_wait_dialog_t
{
  GtkWidget *dialog;
} drawlayer_wait_dialog_t;
 
#include "drawlayer/conf.c"
#include "drawlayer/coordinates.c"
#include "control/signal.h"
 
static void _brush_pipeline_color_from_display(dt_iop_module_t *self, const float display_rgb[3], float pipeline_rgb[3])
{
  if(!display_rgb || IS_NULL_PTR(pipeline_rgb)) return;
 
  pipeline_rgb[0] = _clamp01(display_rgb[0]);
  pipeline_rgb[1] = _clamp01(display_rgb[1]);
  pipeline_rgb[2] = _clamp01(display_rgb[2]);
 
  if(!IS_NULL_PTR(self) && self->dev && self->dev->pipe)
  {
    const dt_iop_order_iccprofile_info_t *const display_profile
        = dt_ioppr_get_pipe_output_profile_info(self->dev->pipe);
    const dt_iop_order_iccprofile_info_t *const work_profile
        = dt_ioppr_get_iop_work_profile_info(self, self->dev->iop);
    if(!IS_NULL_PTR(display_profile) && !IS_NULL_PTR(work_profile))
    {
      float in[4] = { pipeline_rgb[0], pipeline_rgb[1], pipeline_rgb[2], 0.0f };
      float out[4] = { pipeline_rgb[0], pipeline_rgb[1], pipeline_rgb[2], 0.0f };
      dt_ioppr_transform_image_colorspace_rgb(in, out, 1, 1, display_profile, work_profile,
                                              "drawlayer brush color");
      pipeline_rgb[0] = out[0];
      pipeline_rgb[1] = out[1];
      pipeline_rgb[2] = out[2];
    }
  }
 
  const float gain = exp2f(_conf_hdr_exposure());
  pipeline_rgb[0] *= gain;
  pipeline_rgb[1] *= gain;
  pipeline_rgb[2] *= gain;
}
 
static void _sync_cached_brush_colors(dt_iop_module_t *self, const float display_rgb[3])
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !display_rgb) return;
 
  g->ui.brush_display_color[0] = _clamp01(display_rgb[0]);
  g->ui.brush_display_color[1] = _clamp01(display_rgb[1]);
  g->ui.brush_display_color[2] = _clamp01(display_rgb[2]);
  _brush_pipeline_color_from_display(self, g->ui.brush_display_color, g->ui.brush_pipeline_color);
  g->ui.brush_color_valid = TRUE;
}
 
static void _fill_input_brush_settings(dt_iop_module_t *self, dt_drawlayer_paint_raw_input_t *input)
{
  if(IS_NULL_PTR(self) || IS_NULL_PTR(input)) return;
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
 
  uint32_t map_flags = 0u;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SIZE)) map_flags |= DRAWLAYER_INPUT_MAP_PRESSURE_SIZE;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_OPACITY)) map_flags |= DRAWLAYER_INPUT_MAP_PRESSURE_OPACITY;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_FLOW)) map_flags |= DRAWLAYER_INPUT_MAP_PRESSURE_FLOW;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SOFTNESS)) map_flags |= DRAWLAYER_INPUT_MAP_PRESSURE_SOFTNESS;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SIZE)) map_flags |= DRAWLAYER_INPUT_MAP_TILT_SIZE;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_OPACITY)) map_flags |= DRAWLAYER_INPUT_MAP_TILT_OPACITY;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_FLOW)) map_flags |= DRAWLAYER_INPUT_MAP_TILT_FLOW;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SOFTNESS)) map_flags |= DRAWLAYER_INPUT_MAP_TILT_SOFTNESS;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SIZE)) map_flags |= DRAWLAYER_INPUT_MAP_ACCEL_SIZE;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_OPACITY)) map_flags |= DRAWLAYER_INPUT_MAP_ACCEL_OPACITY;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_FLOW)) map_flags |= DRAWLAYER_INPUT_MAP_ACCEL_FLOW;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SOFTNESS)) map_flags |= DRAWLAYER_INPUT_MAP_ACCEL_SOFTNESS;
 
  float display_rgb[3] = { 0.0f };
  float pipeline_rgb[3] = { 0.0f };
  if(!IS_NULL_PTR(g) && g->ui.brush_color_valid)
  {
    memcpy(display_rgb, g->ui.brush_display_color, sizeof(display_rgb));
    memcpy(pipeline_rgb, g->ui.brush_pipeline_color, sizeof(pipeline_rgb));
  }
  else
  {
    _conf_display_color(display_rgb);
    if(!IS_NULL_PTR(g)) _sync_cached_brush_colors(self, display_rgb);
    if(!IS_NULL_PTR(g) && g->ui.brush_color_valid)
    {
      memcpy(display_rgb, g->ui.brush_display_color, sizeof(display_rgb));
      memcpy(pipeline_rgb, g->ui.brush_pipeline_color, sizeof(pipeline_rgb));
    }
    else
    {
      _brush_pipeline_color_from_display(self, display_rgb, pipeline_rgb);
      display_rgb[0] = _clamp01(display_rgb[0]);
      display_rgb[1] = _clamp01(display_rgb[1]);
      display_rgb[2] = _clamp01(display_rgb[2]);
    }
  }
 
  input->map_flags = map_flags;
  input->pressure_profile = (uint8_t)_conf_mapping_profile(DRAWLAYER_CONF_PRESSURE_PROFILE);
  input->tilt_profile = (uint8_t)_conf_mapping_profile(DRAWLAYER_CONF_TILT_PROFILE);
  input->accel_profile = (uint8_t)_conf_mapping_profile(DRAWLAYER_CONF_ACCEL_PROFILE);
  input->distance_percent = _conf_distance() / 100.0f;
  input->smoothing_percent = _conf_smoothing() / 100.0f;
  input->brush_radius = _conf_size();
  input->brush_opacity = _conf_opacity() / 100.0f;
  input->brush_flow = _conf_flow() / 100.0f;
  input->brush_hardness = _conf_hardness();
  input->brush_sprinkles = _conf_sprinkles() / 100.0f;
  input->brush_sprinkle_size = _conf_sprinkle_size();
  input->brush_sprinkle_coarseness = _conf_sprinkle_coarseness() / 100.0f;
  input->brush_shape = _conf_brush_shape();
  input->brush_mode = _conf_brush_mode();
  input->color[0] = pipeline_rgb[0];
  input->color[1] = pipeline_rgb[1];
  input->color[2] = pipeline_rgb[2];
  input->display_color[0] = display_rgb[0];
  input->display_color[1] = display_rgb[1];
  input->display_color[2] = display_rgb[2];
}
 
static void _fill_input_layer_coords(dt_iop_module_t *self, dt_drawlayer_paint_raw_input_t *input)
{
  if(IS_NULL_PTR(input)) return;
  input->have_layer_coords = FALSE;
  input->lx = 0.0f;
  input->ly = 0.0f;
  if(IS_NULL_PTR(self)) return;
 
  float lx = 0.0f;
  float ly = 0.0f;
  if(dt_drawlayer_widget_to_layer_coords(self, input->wx, input->wy, &lx, &ly))
  {
    input->lx = lx;
    input->ly = ly;
    input->have_layer_coords = TRUE;
  }
 
  if(dt_get_debug_flags() & DT_DEBUG_INPUT)
    dt_print(DT_DEBUG_INPUT,
             "[drawlayer] raw-input batch=%u event=%u pos=%u widget=(%.3f,%.3f) raster=(%.3f,%.3f) ok=%d\n",
             input->stroke_batch, input->event_index, input->stroke_pos, input->wx, input->wy, input->lx, input->ly,
             input->have_layer_coords ? 1 : 0);
}
 
static gboolean _layer_name_non_empty(const char *name)
{
  if(IS_NULL_PTR(name)) return FALSE;
  char tmp[DRAWLAYER_NAME_SIZE] = { 0 };
  g_strlcpy(tmp, name, sizeof(tmp));
  g_strstrip(tmp);
  return tmp[0] != '\0';
}
 
static gboolean _get_current_work_profile_key(dt_iop_module_t *self, GList *iop_list, dt_dev_pixelpipe_t *pipe,
                                              char *key, const size_t key_size)
{
  if(IS_NULL_PTR(key) || key_size == 0) return FALSE;
  key[0] = '\0';
  if(IS_NULL_PTR(self) || IS_NULL_PTR(pipe) || !iop_list) return FALSE;
 
  const dt_iop_order_iccprofile_info_t *const work_profile = dt_ioppr_get_iop_work_profile_info(self, iop_list);
  if(IS_NULL_PTR(work_profile)) return FALSE;
 
  g_snprintf(key, key_size, "%d|%d|%s", (int)work_profile->type, (int)work_profile->intent,
             work_profile->filename);
  return key[0] != '\0';
}
 
typedef struct drawlayer_process_scratch_t
{
  float *layerbuf;
  size_t layerbuf_pixels;
  float *cl_background_rgba;
  size_t cl_background_rgba_pixels;
  float *flush_update_rgba;
  size_t flush_update_rgba_pixels;
} drawlayer_process_scratch_t;
 
static void _destroy_process_scratch(gpointer data)
{
  drawlayer_process_scratch_t *scratch = (drawlayer_process_scratch_t *)data;
  if(IS_NULL_PTR(scratch)) return;
  dt_drawlayer_cache_free_temp_buffer((void **)&scratch->layerbuf, "drawlayer process scratch");
  dt_drawlayer_cache_free_temp_buffer((void **)&scratch->cl_background_rgba, "drawlayer process scratch");
  dt_drawlayer_cache_free_temp_buffer((void **)&scratch->flush_update_rgba, "drawlayer process update scratch");
  dt_free(scratch);
}
 
static GPrivate _drawlayer_process_scratch_key = G_PRIVATE_INIT(_destroy_process_scratch);
 
static drawlayer_process_scratch_t *_get_process_scratch(void)
{
  drawlayer_process_scratch_t *scratch
      = (drawlayer_process_scratch_t *)g_private_get(&_drawlayer_process_scratch_key);
  if(!IS_NULL_PTR(scratch)) return scratch;
 
  scratch = g_malloc0(sizeof(*scratch));
  if(IS_NULL_PTR(scratch)) return NULL;
  g_private_set(&_drawlayer_process_scratch_key, scratch);
  return scratch;
}
 
static inline __attribute__((always_inline)) gboolean _resolve_layer_geometry(dt_iop_module_t *self, const dt_dev_pixelpipe_t *pipe,
                                        const dt_dev_pixelpipe_iop_t *piece, int *layer_width,
                                        int *layer_height, int *origin_x, int *origin_y)
{
  if(!IS_NULL_PTR(layer_width)) *layer_width = 0;
  if(!IS_NULL_PTR(layer_height)) *layer_height = 0;
  if(!IS_NULL_PTR(origin_x)) *origin_x = 0;
  if(!IS_NULL_PTR(origin_y)) *origin_y = 0;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev)) return FALSE;
  /* The canvas has the RAW image's dimensions, in this image's own orientation, and is centred
   * on the module's frame -- the same for every pipe, every zoom and every crop, which is the
   * point of anchoring to it: a crop changes which window of the canvas a render reads, not
   * where the paint sits. See iop/drawlayer/coordinates.h.
   *
   * It used to be the module's own stage frame, lifted back through roi_out.scale. That size
   * moves with every crop, and the authored raster was then fitted onto the new frame -- the
   * paint moved and stretched with the crop.
   *
   * Thumbnail and export pipes may start from a downscaled mipmap; that shrinks the module's
   * frame, not the canvas, and the placement's scale absorbs it. */
  int resolved_width = 0;
  int resolved_height = 0;
  if(!dt_drawlayer_layer_canvas_for_pipe(self, pipe, &resolved_width, &resolved_height)) return FALSE;
 
  (void)piece;
 
  if(!IS_NULL_PTR(layer_width)) *layer_width = resolved_width;
  if(!IS_NULL_PTR(layer_height)) *layer_height = resolved_height;
  return resolved_width > 0 && resolved_height > 0;
}
 
static inline __attribute__((always_inline)) uint64_t _drawlayer_params_cache_hash(const int32_t imgid, const dt_iop_drawlayer_params_t *params,
                                             const int layer_width, const int layer_height)
{
  /* Internal drawlayer base-cache identity must stay stable across transient
   * stroke/hash updates. Key only by image + layer identity + working profile,
   * not by volatile fields (stroke hash, sidecar timestamp...).
   *
   * This keeps the shared base patch line hot across interactive drawing ticks
   * and avoids expensive rekey conflicts/republishing during realtime updates. */
  uint64_t hash = 5381u;
  hash = dt_hash(hash, (const char *)&imgid, sizeof(imgid));
  hash = dt_hash(hash, (const char *)&layer_width, sizeof(layer_width));
  hash = dt_hash(hash, (const char *)&layer_height, sizeof(layer_height));
  if(!IS_NULL_PTR(params))
  {
    hash = dt_hash(hash, params->layer_name, sizeof(params->layer_name));
    hash = dt_hash(hash, (const char *)&params->layer_order, sizeof(params->layer_order));
    hash = dt_hash(hash, params->work_profile, sizeof(params->work_profile));
  }
  return hash ? hash : 1u;
}
 
static gboolean _rekey_shared_base_patch(drawlayer_patch_t *patch, const int32_t imgid,
                                         const dt_iop_drawlayer_params_t *params)
{
  /* Rekeying lets the same pixelpipe cache line keep its allocated storage and
   * current in-memory pixels while the serialized module hash advances to a new
   * history snapshot. This is the central piece that lets other pipelines find
   * the newest base patch through the cache instead of through GUI internals. */
  if(IS_NULL_PTR(patch) || IS_NULL_PTR(patch->cache_entry) || IS_NULL_PTR(params)) return FALSE;
  const uint64_t new_hash = _drawlayer_params_cache_hash(imgid, params, patch->width, patch->height);
  if(new_hash == patch->cache_hash) return TRUE;
  if(dt_dev_pixelpipe_cache_rekey(patch->cache_hash, new_hash, patch->cache_entry) == 0)
  {
    patch->cache_hash = new_hash;
    return TRUE;
  }
 
  /* Fallback path: another cache line already owns `new_hash` (or rekeying
   * failed for any other reason). Publish the current authoritative pixels into
   * that target key explicitly so parallel/headless pipelines resolving by the
   * latest params hash still see up-to-date content.
   *
   * We intentionally keep `patch` bound to its original cache entry/hash here,
   * because this module may hold additional explicit refs on that entry
   * (`base_patch_loaded_ref`, stroke refs). Rebinding `patch` would desynchronize
   * those ref counters. */
  if(IS_NULL_PTR(patch->pixels) || patch->width <= 0 || patch->height <= 0) return FALSE;
 
  drawlayer_patch_t published = { 0 };
  int created = 0;
  if(!dt_drawlayer_cache_patch_alloc_shared(&published, new_hash, (size_t)patch->width * patch->height,
                                            patch->width, patch->height, "drawlayer sidecar cache", &created))
    return FALSE;
 
  dt_drawlayer_cache_patch_rdlock(patch);
  memcpy(published.pixels, patch->pixels, (size_t)patch->width * patch->height * 4 * sizeof(float));
  dt_drawlayer_cache_patch_rdunlock(patch);
#ifdef HAVE_OPENCL
  dt_dev_pixelpipe_cache_flush_host_pinned_image(published.pixels,
                                                 published.cache_entry, -1);
#endif
  dt_drawlayer_cache_patch_clear(&published, "drawlayer patch");
  if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
    dt_print(DT_DEBUG_PERF,
             "[drawlayer] cache rekey conflict old=%" PRIu64 " new=%" PRIu64 " -> published snapshot instead\n",
             patch->cache_hash, new_hash);
  return TRUE;
}
 
static void _retain_base_patch_loaded_ref(dt_iop_drawlayer_gui_data_t *g)
{
  if(IS_NULL_PTR(g) || IS_NULL_PTR(g->process.base_patch.cache_entry) || g->process.base_patch_loaded_ref) return;
  dt_dev_pixelpipe_cache_ref_count_entry(TRUE, g->process.base_patch.cache_entry);
  g->process.base_patch_loaded_ref = TRUE;
}
 
static void _retain_base_patch_stroke_ref(dt_iop_drawlayer_gui_data_t *g)
{
  if(IS_NULL_PTR(g) || IS_NULL_PTR(g->process.base_patch.cache_entry)) return;
  dt_dev_pixelpipe_cache_ref_count_entry(TRUE, g->process.base_patch.cache_entry);
  g->process.base_patch_stroke_refs++;
}
 
void dt_drawlayer_release_all_base_patch_extra_refs(dt_iop_drawlayer_gui_data_t *g)
{
  if(IS_NULL_PTR(g)) return;
  if(IS_NULL_PTR(g->process.base_patch.cache_entry))
  {
    /* Keep refcount bookkeeping state coherent even if the cache entry has
     * already been detached/cleared. This prevents stale counters from being
     * applied to a future reused `g->process.base_patch` entry. */
    g->process.base_patch_loaded_ref = FALSE;
    g->process.base_patch_stroke_refs = 0;
    return;
  }
 
  if(g->process.base_patch_loaded_ref)
  {
    dt_dev_pixelpipe_cache_ref_count_entry(FALSE, g->process.base_patch.cache_entry);
    g->process.base_patch_loaded_ref = FALSE;
  }
 
  while(g->process.base_patch_stroke_refs > 0)
  {
    dt_dev_pixelpipe_cache_ref_count_entry(FALSE, g->process.base_patch.cache_entry);
    g->process.base_patch_stroke_refs--;
  }
}
 
static inline __attribute__((always_inline)) gboolean _refresh_piece_base_cache(dt_iop_module_t *self, dt_iop_drawlayer_data_t *data,
                                          const dt_iop_drawlayer_params_t *params, dt_dev_pixelpipe_t *pipe,
                                          dt_dev_pixelpipe_iop_t *piece)
{
  if(IS_NULL_PTR(self) || IS_NULL_PTR(data) || IS_NULL_PTR(params) || IS_NULL_PTR(piece)) return FALSE;
  if(params->layer_name[0] == '\0')
  {
    dt_drawlayer_cache_patch_clear(&data->process.base_patch, "drawlayer patch");
    data->process.cache_valid = FALSE;
    data->process.cache_dirty = FALSE;
    dt_drawlayer_paint_runtime_state_reset(&data->process.cache_dirty_rect);
    data->process.cache_imgid = -1;
    data->process.cache_layer_name[0] = '\0';
    data->process.cache_layer_order = -1;
    dt_drawlayer_process_state_invalidate(&data->process);
    return TRUE;
  }
 
  /* Display heartbeats hit this path for every pipeline pass. When the current
   * in-memory patch already matches the selected layer identity and geometry,
   * stay entirely in RAM and skip sidecar probing altogether. Layer names are
   * the stable identity here; page order is only a lookup hint and may drift
   * after sidecar rewrites without invalidating the pixels already cached. */
  if(data->process.cache_valid && data->process.base_patch.cache_entry
     && data->process.cache_imgid == pipe->dev->image_storage.id
     && !g_strcmp0(data->process.cache_layer_name, params->layer_name)
     && data->process.base_patch.width > 0 && data->process.base_patch.height > 0)
  {
    const uint64_t cached_hash = _drawlayer_params_cache_hash(pipe->dev->image_storage.id, params,
                                                              data->process.base_patch.width,
                                                              data->process.base_patch.height);
    if(data->process.base_patch.cache_hash == cached_hash)
      return TRUE;
  }
 
  char path[DT_PATH_MAX] = { 0 };
  const gboolean have_sidecar_path = dt_drawlayer_io_sidecar_path(pipe->dev->image_storage.id, path, sizeof(path));
  const gboolean have_sidecar = have_sidecar_path && g_file_test(path, G_FILE_TEST_EXISTS);
  dt_drawlayer_io_layer_info_t info = { 0 };
  if(have_sidecar)
    dt_drawlayer_io_find_layer(path, params->layer_name, params->layer_order, &info);
 
  int layer_width = 0;
  int layer_height = 0;
  const gboolean have_pipe_geometry = _resolve_layer_geometry(self, pipe, piece, &layer_width, &layer_height, NULL, NULL);
 
  /* The canvas is the raw frame in every pipe, so the stored page's own dimensions are no longer
   * consulted to decide it -- they used to be, because a thumbnail or export pipe resolved a
   * SMALLER canvas than the darkroom did (both followed the module's stage frame, and those pipes
   * render downscaled), and reinterpreting the page at that size recentred it. Anchoring removes
   * the divergence rather than papering over it: one canvas size for every pipe, and the pipe's
   * own scale is absorbed by the placement.
   *
   * A page authored before this change was written in the post-crop frame and will be read as
   * though it were raw, so it appears shifted until repainted. That was the agreed trade; the
   * alternative was a versioned sidecar and a migration pass. */
  if(!have_pipe_geometry)
  {
    if(info.found && info.width > 0 && info.height > 0)
    {
      layer_width = (int)info.width;
      layer_height = (int)info.height;
    }
    else
      return FALSE;
  }
 
  const uint64_t base_hash = _drawlayer_params_cache_hash(pipe->dev->image_storage.id, params, layer_width, layer_height);
  if(data->process.cache_valid && data->process.base_patch.cache_entry
     && data->process.base_patch.cache_hash == base_hash && data->process.cache_imgid == pipe->dev->image_storage.id
     && !g_strcmp0(data->process.cache_layer_name, params->layer_name))
    return TRUE;
 
  dt_drawlayer_cache_patch_clear(&data->process.base_patch, "drawlayer patch");
  data->process.cache_valid = FALSE;
  data->process.cache_dirty = FALSE;
  dt_drawlayer_paint_runtime_state_reset(&data->process.cache_dirty_rect);
  data->process.cache_imgid = -1;
  data->process.cache_layer_name[0] = '\0';
  data->process.cache_layer_order = -1;
  dt_drawlayer_process_state_invalidate(&data->process);
 
  if(layer_width > 0 && layer_height > 0)
  {
    int created = 0;
    if(!dt_drawlayer_cache_patch_alloc_shared(&data->process.base_patch,
                                              _drawlayer_params_cache_hash(pipe->dev->image_storage.id, params, layer_width,
                                                                           layer_height),
                                              (size_t)layer_width * layer_height, layer_width, layer_height,
                                              "drawlayer sidecar cache", &created))
      return FALSE;
 
    if(!created)
    {
      data->process.cache_valid = TRUE;
      data->process.cache_imgid = pipe->dev->image_storage.id;
      g_strlcpy(data->process.cache_layer_name, params->layer_name, sizeof(data->process.cache_layer_name));
      data->process.cache_layer_order = params->layer_order;
      return TRUE;
    }
 
    gboolean warm_loaded = FALSE;
    if(have_sidecar && info.found)
    {
      dt_drawlayer_io_patch_t warm_patch = { 0 };
      dt_drawlayer_cache_patch_wrlock(&data->process.base_patch);
      warm_patch.x = data->process.base_patch.x;
      warm_patch.y = data->process.base_patch.y;
      warm_patch.width = data->process.base_patch.width;
      warm_patch.height = data->process.base_patch.height;
      warm_patch.pixels = data->process.base_patch.pixels;
      warm_loaded = dt_drawlayer_io_load_layer(path, params->layer_name, params->layer_order, layer_width,
                                               layer_height, &warm_patch);
      dt_drawlayer_cache_patch_wrunlock(&data->process.base_patch);
    }
 
    if(warm_loaded)
    {
      data->process.cache_valid = TRUE;
      data->process.cache_imgid = pipe->dev->image_storage.id;
      g_strlcpy(data->process.cache_layer_name, params->layer_name, sizeof(data->process.cache_layer_name));
      data->process.cache_layer_order = info.found ? info.index : params->layer_order;
      dt_drawlayer_paint_runtime_state_reset(&data->process.cache_dirty_rect);
      return TRUE;
    }
 
    data->process.cache_valid = TRUE;
    data->process.cache_dirty = FALSE;
    dt_drawlayer_paint_runtime_state_reset(&data->process.cache_dirty_rect);
    data->process.cache_imgid = pipe->dev->image_storage.id;
    g_strlcpy(data->process.cache_layer_name, params->layer_name, sizeof(data->process.cache_layer_name));
    data->process.cache_layer_order = info.found ? info.index : params->layer_order;
    return TRUE;
  }
  return FALSE;
}
 
__DT_CLONE_TARGETS__
static void _blend_layer_over_input(float *output, const float *input, const float *layerbuf, const size_t pixels,
                                    const gboolean use_preview_bg, const float preview_bg)
{
  if(IS_NULL_PTR(output) || IS_NULL_PTR(input) || IS_NULL_PTR(layerbuf) || pixels == 0) return;
 
  const dt_aligned_pixel_simd_t preview_base = { preview_bg, preview_bg, preview_bg, 1.0f };
  __OMP_PARALLEL_FOR__()
  for(size_t kk = 0; kk < pixels; kk++)
  {
    const float *base = input + 4 * kk;
    const float *layer = layerbuf + 4 * kk;
    float *pixel = output + 4 * kk;
    const float src_alpha = _clamp01(layer[3]);
    if(src_alpha > 1e-8f)
    {
      const dt_aligned_pixel_simd_t base_v = use_preview_bg ? preview_base : dt_load_simd_aligned(base);
      dt_aligned_pixel_simd_t src_v = dt_load_simd_aligned(layer);
      const float inv_alpha = 1.0f - src_alpha;
      const dt_aligned_pixel_simd_t inv_alpha_v = { inv_alpha, inv_alpha, inv_alpha, inv_alpha };
      src_v[3] = src_alpha;
      dt_store_simd_aligned(pixel, src_v + base_v * inv_alpha_v);
    }
    else
    {
      const dt_aligned_pixel_simd_t base_v = use_preview_bg ? preview_base : dt_load_simd_aligned(base);
      dt_store_simd_aligned(pixel, base_v);
    }
  }
}
 
#ifdef HAVE_OPENCL
typedef struct drawlayer_cl_image_handle_t
{
  cl_mem mem;
  gboolean is_pinned;
  gboolean is_cached_device;
} drawlayer_cl_image_handle_t;
 
static gboolean _drawlayer_sync_host_image_to_device(const int devid, cl_mem device_image, void *host_pixels,
                                                     const int width, const int height, const int bpp,
                                                     const dt_drawlayer_damaged_rect_t *dirty_rect)
{
  if(IS_NULL_PTR(device_image) || IS_NULL_PTR(host_pixels) || width <= 0 || height <= 0 || bpp <= 0) return FALSE;
 
  if(dirty_rect && dirty_rect->valid)
  {
    const int dirty_x0 = CLAMP(dirty_rect->nw[0], 0, width);
    const int dirty_y0 = CLAMP(dirty_rect->nw[1], 0, height);
    const int dirty_x1 = CLAMP(dirty_rect->se[0], 0, width);
    const int dirty_y1 = CLAMP(dirty_rect->se[1], 0, height);
    const int dirty_w = dirty_x1 - dirty_x0;
    const int dirty_h = dirty_y1 - dirty_y0;
    if(dirty_w > 0 && dirty_h > 0 && (dirty_w < width || dirty_h < height))
    {
      const size_t origin[] = { (size_t)dirty_x0, (size_t)dirty_y0, 0 };
      const size_t region[] = { (size_t)dirty_w, (size_t)dirty_h, 1 };
      char *host_origin = (char *)host_pixels + ((size_t)dirty_y0 * width + dirty_x0) * (size_t)bpp;
      if(dt_opencl_write_host_to_device_raw(devid, host_origin, device_image, origin, region, width * bpp,
                                            CL_TRUE) == CL_SUCCESS)
        return TRUE;
    }
  }
 
  if(dt_opencl_is_pinned_memory(device_image))
  {
    void *mapped = dt_opencl_map_image(devid, device_image, TRUE, CL_MAP_WRITE, width, height, bpp);
    if(dt_opencl_unmap_mem_object(devid, device_image, mapped) == CL_SUCCESS)
      return TRUE;
  }
 
  return dt_opencl_write_host_to_device(devid, host_pixels, device_image, width, height, bpp) == CL_SUCCESS;
}
 
static gboolean _drawlayer_acquire_source_image(const int devid, const float *layer_pixels,
                                                dt_pixel_cache_entry_t *resolved_entry,
                                                const gboolean force_device_copy, const gboolean realtime_reuse,
                                                const int source_w, const int source_h,
                                                dt_drawlayer_process_state_t *process,
                                                drawlayer_cl_image_handle_t *source)
{
  if(IS_NULL_PTR(source) || IS_NULL_PTR(layer_pixels) || source_w <= 0 || source_h <= 0) return FALSE;
  *source = (drawlayer_cl_image_handle_t){ 0 };
 
  if(force_device_copy)
  {
    source->mem
        = dt_opencl_copy_host_to_device(devid, (void *)layer_pixels, source_w, source_h, 4 * sizeof(float));
    return !IS_NULL_PTR(source->mem);
  }
 
  /* Realtime redraws keep revisiting the same host-backed layer cache. Prefer a
   * reusable device buffer first so the blend path can stay asynchronous instead
   * of forcing a full `dt_opencl_finish()` before the base patch lock is released. */
  if(realtime_reuse && resolved_entry)
  {
    const dt_iop_roi_t source_roi = { .width = source_w, .height = source_h };
    gboolean reused_from_cache = FALSE;
    source->mem = dt_dev_pixelpipe_cache_get_cl_buffer(devid, NULL, &source_roi, 4 * sizeof(float), NULL,
                                                       "drawlayer source", resolved_entry,
                                                       &reused_from_cache, NULL);
    if(source->mem)
    {
      const dt_drawlayer_damaged_rect_t *dirty_rect
          = (reused_from_cache && process) ? &process->cache_dirty_rect : NULL;
      if(_drawlayer_sync_host_image_to_device(devid, source->mem, (void *)layer_pixels, source_w, source_h,
                                              4 * sizeof(float), dirty_rect))
      {
        source->is_cached_device = TRUE;
        if(process) dt_drawlayer_paint_runtime_state_reset(&process->cache_dirty_rect);
        return TRUE;
      }
 
      dt_dev_pixelpipe_cache_release_cl_buffer((void **)&source->mem, resolved_entry, NULL, FALSE);
    }
  }
 
  source->mem = dt_dev_pixelpipe_cache_get_pinned_image(
      (void *)layer_pixels, resolved_entry, devid, source_w, source_h,
      4 * sizeof(float), CL_MEM_READ_WRITE | CL_MEM_USE_HOST_PTR, NULL);
  if(source->mem)
  {
    source->is_pinned = TRUE;
    return TRUE;
  }
 
  source->mem = dt_opencl_alloc_device_use_host_pointer(
      devid, source_w, source_h, 4 * sizeof(float), (void *)layer_pixels, CL_MEM_READ_WRITE | CL_MEM_USE_HOST_PTR);
  if(source->mem)
  {
    if(_drawlayer_sync_host_image_to_device(devid, source->mem, (void *)layer_pixels, source_w, source_h,
                                            4 * sizeof(float), NULL))
    {
      source->is_pinned = TRUE;
      return TRUE;
    }
 
    dt_opencl_release_mem_object(source->mem);
    source->mem = NULL;
  }
 
  source->mem = dt_opencl_copy_host_to_device(devid, (void *)layer_pixels, source_w, source_h, 4 * sizeof(float));
  return !IS_NULL_PTR(source->mem);
}
 
static int _drawlayer_copy_or_resample_layer_roi(const int devid, cl_mem dev_source_rgba, cl_mem dev_layer_rgba,
                                                 const int source_w, const int source_h,
                                                 const dt_iop_roi_t *const target_roi,
                                                 const dt_iop_roi_t *const source_roi)
{
  const gboolean can_copy_crop
      = (fabs(target_roi->scale - 1.0) <= 1e-6 && target_roi->x >= 0
         && target_roi->y >= 0 && target_roi->x + target_roi->width <= source_w
         && target_roi->y + target_roi->height <= source_h);
  if(can_copy_crop)
  {
    size_t src_origin[3] = { (size_t)target_roi->x, (size_t)target_roi->y, 0 };
    size_t dst_origin[3] = { 0, 0, 0 };
    size_t region[3] = { (size_t)target_roi->width, (size_t)target_roi->height, 1 };
    const int copy_err
        = dt_opencl_enqueue_copy_image(devid, dev_source_rgba, dev_layer_rgba, src_origin, dst_origin, region);
    if(copy_err == CL_SUCCESS) return CL_SUCCESS;
  }
 
  /* Force bilinear for the layer matte. The premultiplied-alpha brush stroke is
   * stamped at full canvas resolution, so this resample only ever previews it at
   * display scale (mostly downscaling). Bilinear is the only kernel here with no
   * negative lobes: it cannot overshoot, so it never rings/halos at stroke edges
   * nor pushes alpha out of [0,1] — unlike the user-pref default (Lanczos) or the
   * Catmull-Rom "bicubic". On minification dt_interpolation_resample widens the
   * tap support, so bilinear acts as a clean area filter (no aliasing). */
  const struct dt_interpolation *const itor = dt_interpolation_new(DT_INTERPOLATION_BILINEAR);
  return dt_interpolation_resample_cl(itor, devid, dev_layer_rgba, target_roi, dev_source_rgba, source_roi);
}
 
static gboolean _drawlayer_acquire_layer_image(const int devid, dt_pixel_cache_entry_t *resolved_entry,
                                               const gboolean realtime_reuse, const gboolean direct_copy,
                                               cl_mem dev_source_rgba, const int source_w, const int source_h,
                                               const dt_iop_roi_t *const target_roi,
                                               const dt_iop_roi_t *const source_roi,
                                               drawlayer_cl_image_handle_t *layer, int *err)
{
  if(IS_NULL_PTR(layer) || !err || IS_NULL_PTR(target_roi) || IS_NULL_PTR(source_roi)) return FALSE;
  *layer = (drawlayer_cl_image_handle_t){ 0 };
 
  if(direct_copy)
  {
    layer->mem = dev_source_rgba;
    return TRUE;
  }
 
  if(realtime_reuse && resolved_entry)
  {
    layer->mem = dt_dev_pixelpipe_cache_get_cl_buffer(devid, NULL, target_roi, 4 * sizeof(float), NULL,
                                                      "drawlayer layer", resolved_entry, NULL,
                                                      dev_source_rgba);
    layer->is_cached_device = (!IS_NULL_PTR(layer->mem));
  }
 
  if(IS_NULL_PTR(layer->mem))
  {
    layer->mem = dt_opencl_alloc_device(devid, target_roi->width, target_roi->height, 4 * sizeof(float));
  }
 
  if(IS_NULL_PTR(layer->mem))
  {
    *err = CL_MEM_OBJECT_ALLOCATION_FAILURE;
    return FALSE;
  }
 
  *err = _drawlayer_copy_or_resample_layer_roi(devid, dev_source_rgba, layer->mem, source_w, source_h, target_roi,
                                               source_roi);
  return *err == CL_SUCCESS;
}
 
static int _drawlayer_run_premult_over_kernel(const int devid, const int kernel_premult_over,
                                              cl_mem dev_background, cl_mem dev_layer_rgba, cl_mem dev_out,
                                              const int width, const int height, const int background_offset_x,
                                              const int background_offset_y)
{
  const int offs[2] = { background_offset_x, background_offset_y };
  const size_t sizes[] = { ROUNDUPDWD(width, devid), ROUNDUPDHT(height, devid), 1 };
 
  int err = dt_opencl_set_kernel_arg(devid, kernel_premult_over, 0, sizeof(cl_mem), &dev_background);
  err |= dt_opencl_set_kernel_arg(devid, kernel_premult_over, 1, sizeof(cl_mem), &dev_layer_rgba);
  err |= dt_opencl_set_kernel_arg(devid, kernel_premult_over, 2, sizeof(cl_mem), &dev_out);
  err |= dt_opencl_set_kernel_arg(devid, kernel_premult_over, 3, sizeof(int), &width);
  err |= dt_opencl_set_kernel_arg(devid, kernel_premult_over, 4, sizeof(int), &height);
  err |= dt_opencl_set_kernel_arg(devid, kernel_premult_over, 5, sizeof(offs), offs);
  if(err != CL_SUCCESS) return err;
 
  return dt_opencl_enqueue_kernel_2d(devid, kernel_premult_over, sizes);
}
 
/* Influence radius (in target/display pixels) of a changed source pixel through
 * the resampling interpolation. interpolation.c maps a target output pixel to a
 * source window whose half-width is ~support/scale source pixels; transformed
 * back to target space that footprint is ~support pixels regardless of scale, so
 * a fixed, generous target-space margin keeps partial-resample edges seamless. */
#define DRAWLAYER_RESAMPLE_DAMAGE_MARGIN 8
 
/* Map a layer-space (source) damage rectangle to the output (target) display
 * window it affects, padded by the interpolation support so resampled edges stay
 * seamless. Returns TRUE and fills *out (nw inclusive / se exclusive, clamped to
 * the target ROI, in target-local coordinates) only when the mapped window is a
 * strict sub-rect of the target worth a partial composite. */
static gboolean _drawlayer_map_source_damage_to_target(const dt_drawlayer_damaged_rect_t *src_damage,
                                                       const dt_iop_roi_t *const target_roi,
                                                       const dt_iop_roi_t *const source_roi,
                                                       dt_drawlayer_damaged_rect_t *out)
{
  if(IS_NULL_PTR(src_damage) || !src_damage->valid || IS_NULL_PTR(target_roi) || IS_NULL_PTR(source_roi)
     || IS_NULL_PTR(out))
    return FALSE;
  if(target_roi->width <= 0 || target_roi->height <= 0 || target_roi->scale <= 0.0f) return FALSE;
 
  const double scale = target_roi->scale;
  const int margin = DRAWLAYER_RESAMPLE_DAMAGE_MARGIN;
  /* out = (source + source_roi.x) * scale - target_roi.x  (inverse of the
   * interpolation source mapping source = (target_roi.x + out)/scale - source_roi.x). */
  const double sx0 = (double)src_damage->nw[0] + source_roi->x;
  const double sy0 = (double)src_damage->nw[1] + source_roi->y;
  const double sx1 = (double)src_damage->se[0] + source_roi->x;
  const double sy1 = (double)src_damage->se[1] + source_roi->y;
 
  int tx0 = (int)floor(sx0 * scale - target_roi->x) - margin;
  int ty0 = (int)floor(sy0 * scale - target_roi->y) - margin;
  int tx1 = (int)ceil(sx1 * scale - target_roi->x) + margin;
  int ty1 = (int)ceil(sy1 * scale - target_roi->y) + margin;
 
  tx0 = CLAMP(tx0, 0, target_roi->width);
  ty0 = CLAMP(ty0, 0, target_roi->height);
  tx1 = CLAMP(tx1, 0, target_roi->width);
  ty1 = CLAMP(ty1, 0, target_roi->height);
 
  if(tx1 <= tx0 || ty1 <= ty0) return FALSE;
  /* Whole-frame damage is not worth the partial path's bookkeeping. */
  if(tx0 == 0 && ty0 == 0 && tx1 == target_roi->width && ty1 == target_roi->height) return FALSE;
 
  *out = (dt_drawlayer_damaged_rect_t){ .valid = TRUE, .nw = { tx0, ty0 }, .se = { tx1, ty1 } };
  return TRUE;
}
 
static int _blend_layer_over_input_cl(const int devid, const int kernel_premult_over, cl_mem dev_out,
                                      cl_mem dev_in, drawlayer_process_scratch_t *scratch,
                                      const float *layer_pixels, dt_pixel_cache_entry_t *source_entry,
                                      cl_mem source_mem_override, const int source_w, const int source_h,
                                      dt_drawlayer_process_state_t *process,
                                      const dt_iop_roi_t *const target_roi, const dt_iop_roi_t *const source_roi,
                                      const gboolean direct_copy, const gboolean use_preview_bg,
                                      const float preview_bg, const gboolean realtime_reuse,
                                      const gboolean force_device_copy, const gboolean allow_partial)
{
  if(devid < 0 || IS_NULL_PTR(dev_out) || IS_NULL_PTR(dev_in) || IS_NULL_PTR(scratch) || (IS_NULL_PTR(layer_pixels) && !source_mem_override) || source_w <= 0
     || source_h <= 0 || !target_roi || target_roi->width <= 0 || target_roi->height <= 0)
    return FALSE;
  if(kernel_premult_over < 0) return FALSE;
 
  dt_pixel_cache_entry_t *resolved_entry = source_entry;
  gboolean resolved_entry_ref = FALSE;
  if(realtime_reuse && !resolved_entry)
  {
    resolved_entry
        = dt_dev_pixelpipe_cache_ref_entry_for_host_ptr((void *)layer_pixels);
    resolved_entry_ref = (!IS_NULL_PTR(resolved_entry));
  }
 
  /* Realtime partial composite: when the caller validated that dev_out still
   * holds this node's previous full composite (same buffer, hash and geometry)
   * and only the painted sub-rect of the layer changed, refresh just that window
   * instead of re-resampling the whole display. The source-damage rectangle must
   * be snapshotted here because _drawlayer_acquire_source_image() consumes (and
   * resets) process->cache_dirty_rect while uploading the dirty source region. */
  dt_drawlayer_damaged_rect_t target_damage = { 0 };
  const gboolean partial = allow_partial && !use_preview_bg && !direct_copy && !source_mem_override && process
                           && _drawlayer_map_source_damage_to_target(&process->cache_dirty_rect, target_roi,
                                                                     source_roi, &target_damage);
 
  drawlayer_cl_image_handle_t source = { 0 };
  drawlayer_cl_image_handle_t layer = { 0 };
  cl_mem dev_layer_partial = NULL;
  cl_mem dev_bg_partial = NULL;
  cl_mem dev_out_partial = NULL;
  cl_mem dev_background = NULL;
  int err = CL_SUCCESS;
  int result = FALSE;
  if(source_mem_override)
    source.mem = source_mem_override;
  else if(!_drawlayer_acquire_source_image(devid, layer_pixels, resolved_entry, force_device_copy, realtime_reuse,
                                           source_w, source_h, process, &source))
    goto cleanup;
 
  if(partial)
  {
    const int dw = target_damage.se[0] - target_damage.nw[0];
    const int dh = target_damage.se[1] - target_damage.nw[1];
    size_t win_origin[3] = { (size_t)target_damage.nw[0], (size_t)target_damage.nw[1], 0 };
    size_t zero_origin[3] = { 0, 0, 0 };
    size_t win_region[3] = { (size_t)dw, (size_t)dh, 1 };
 
    /* All three windows are damage-sized device scratch buffers. We keep the
     * unmodified full-frame `blendop_premult_over` kernel (local 0,0 coords) and
     * stage the sub-window through copies so the GPU kernel ABI never changes:
     *   layer_partial = resample(source, damaged display window)
     *   bg_partial    = dev_in[window]                       (background slice)
     *   out_partial   = over(layer_partial, bg_partial)      (full-window kernel)
     *   dev_out[window] = out_partial                        (refresh in place)
     * The rest of dev_out keeps the previous full composite. */
    dev_layer_partial = dt_opencl_alloc_device(devid, dw, dh, 4 * sizeof(float));
    dev_bg_partial = dt_opencl_alloc_device(devid, dw, dh, 4 * sizeof(float));
    dev_out_partial = dt_opencl_alloc_device(devid, dw, dh, 4 * sizeof(float));
    if(IS_NULL_PTR(dev_layer_partial) || IS_NULL_PTR(dev_bg_partial) || IS_NULL_PTR(dev_out_partial))
    {
      err = CL_MEM_OBJECT_ALLOCATION_FAILURE;
      goto cleanup;
    }
    /* Resample only the damaged display window from the full-res source. The
     * sub-window's global target origin maps back to the correct source region
     * through the unchanged interpolation source mapping. */
    const dt_iop_roi_t sub_target_roi = {
      .x = target_roi->x + target_damage.nw[0],
      .y = target_roi->y + target_damage.nw[1],
      .width = dw,
      .height = dh,
      .scale = target_roi->scale,
    };
    err = _drawlayer_copy_or_resample_layer_roi(devid, source.mem, dev_layer_partial, source_w, source_h,
                                                &sub_target_roi, source_roi);
    if(err != CL_SUCCESS) goto cleanup;
 
    err = dt_opencl_enqueue_copy_image(devid, dev_in, dev_bg_partial, win_origin, zero_origin, win_region);
    if(err != CL_SUCCESS) goto cleanup;
 
    err = _drawlayer_run_premult_over_kernel(devid, kernel_premult_over, dev_bg_partial, dev_layer_partial,
                                             dev_out_partial, dw, dh, 0, 0);
    if(err != CL_SUCCESS) goto cleanup;
 
    err = dt_opencl_enqueue_copy_image(devid, dev_out_partial, dev_out, zero_origin, win_origin, win_region);
    if(err != CL_SUCCESS) goto cleanup;
 
    if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
      dt_print(DT_DEBUG_PERF, "[drawlayer] partial composite window=%dx%d at (%d,%d) of %dx%d\n", dw, dh,
               target_damage.nw[0], target_damage.nw[1], target_roi->width, target_roi->height);
 
    if(source.is_pinned)
    {
      if(!dt_opencl_finish(devid))
      {
        err = -1;
        goto cleanup;
      }
    }
    result = TRUE;
    goto cleanup;
  }
 
  if(!_drawlayer_acquire_layer_image(devid, resolved_entry, realtime_reuse, direct_copy, source.mem, source_w,
                                     source_h, target_roi, source_roi, &layer, &err))
    goto cleanup;
 
  if(use_preview_bg)
  {
    const size_t out_pixels = (size_t)target_roi->width * target_roi->height;
    float *background = dt_drawlayer_cache_ensure_scratch_buffer(&scratch->cl_background_rgba,
                                                                 &scratch->cl_background_rgba_pixels, out_pixels,
                                                                 "drawlayer process scratch");
    if(IS_NULL_PTR(background)) goto cleanup;
    __OMP_PARALLEL_FOR__(if(out_pixels > 4096))
    for(size_t kk = 0; kk < out_pixels; kk++)
    {
      float *pixel = background + 4 * kk;
      pixel[0] = preview_bg;
      pixel[1] = preview_bg;
      pixel[2] = preview_bg;
      pixel[3] = 1.0f;
    }
    dev_background = dt_dev_pixelpipe_cache_get_pinned_image(
        background, NULL, devid, target_roi->width, target_roi->height,
        4 * sizeof(float), CL_MEM_READ_WRITE | CL_MEM_USE_HOST_PTR, NULL);
    if(IS_NULL_PTR(dev_background)) goto cleanup;
  }
  else
    dev_background = dev_in;
 
  err = _drawlayer_run_premult_over_kernel(devid, kernel_premult_over, dev_background, layer.mem, dev_out,
                                           target_roi->width, target_roi->height, 0, 0);
  if(err != CL_SUCCESS) goto cleanup;
 
  /* The realtime display source is the host-backed full-resolution cache.
   * When imported as CL_MEM_USE_HOST_PTR, queued GPU reads may still touch that
   * host memory after process_cl() returns. Finish the queue before releasing
   * the cache lock whenever the layer source is host-backed. */
  if(source.is_pinned)
  {
    if(!dt_opencl_finish(devid))
    {
      err = -1;
      goto cleanup;
    }
  }
 
  result = TRUE;
 
cleanup:
  if(dev_layer_partial) dt_opencl_release_mem_object(dev_layer_partial);
  if(dev_bg_partial) dt_opencl_release_mem_object(dev_bg_partial);
  if(dev_out_partial) dt_opencl_release_mem_object(dev_out_partial);
  if(use_preview_bg)
    dt_dev_pixelpipe_cache_put_pinned_image(scratch->cl_background_rgba, NULL,
                                            (void **)&dev_background);
  if(layer.mem && layer.mem != source.mem)
  {
    if(layer.is_cached_device && resolved_entry)
      dt_dev_pixelpipe_cache_release_cl_buffer((void **)&layer.mem, resolved_entry, NULL, TRUE);
    else
      dt_opencl_release_mem_object(layer.mem);
  }
  if(!source_mem_override && source.is_pinned)
    dt_dev_pixelpipe_cache_put_pinned_image((void *)layer_pixels, resolved_entry,
                                            (void **)&source.mem);
  else if(!source_mem_override && source.is_cached_device && resolved_entry)
    dt_dev_pixelpipe_cache_release_cl_buffer((void **)&source.mem, resolved_entry, NULL, TRUE);
  else if(!source_mem_override && source.mem)
    dt_opencl_release_mem_object(source.mem);
  if(resolved_entry_ref)
    dt_dev_pixelpipe_cache_ref_count_entry(FALSE, resolved_entry);
 
  if(err != CL_SUCCESS) dt_print(DT_DEBUG_OPENCL, "[drawlayer] process_cl blend path failed: %d\n\n", err);
 
  return result;
}
#endif
 
static gboolean _profile_key_is_sane(const char *value)
{
  if(IS_NULL_PTR(value) || value[0] == '\0') return FALSE;
 
  int separators = 0;
  for(const unsigned char *c = (const unsigned char *)value; *c; c++)
  {
    if(*c == '|')
      separators++;
    else if(!g_ascii_isprint(*c))
      return FALSE;
  }
 
  return separators >= 2;
}
 
static int64_t _sidecar_timestamp_from_path(const char *path)
{
  if(IS_NULL_PTR(path) || path[0] == '\0' || !g_file_test(path, G_FILE_TEST_EXISTS)) return 0;
 
  GStatBuf st = { 0 };
  if(g_stat(path, &st) != 0) return 0;
  return (int64_t)st.st_mtime;
}
 
static void _ensure_cursor_stamp_surface(dt_iop_module_t *self, const float widget_radius, const float opacity,
                                         const float hardness)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || widget_radius <= 0.0f) return;
 
  const double ppd = (dt_gui_get_global() && dt_gui_get_global()->ppd > 0.0) ? dt_gui_get_global()->ppd : 1.0;
  float display_rgb[3] = { 0.0f };
  _conf_display_color(display_rgb);
  const int shape = _conf_brush_shape();
  const int size_px = MAX(2, (int)ceil((2.0f * widget_radius + 2.0f) * ppd));
 
  const gboolean needs_rebuild
      = !g->ui.cursor_surface || g->ui.cursor_surface_size != size_px || fabs(g->ui.cursor_surface_ppd - ppd) > 1e-9
        || fabsf(g->ui.cursor_radius - widget_radius) > 1e-3f || fabsf(g->ui.cursor_opacity - opacity) > 1e-6f
        || fabsf(g->ui.cursor_hardness - hardness) > 1e-6f || g->ui.cursor_shape != shape
        || fabsf(g->ui.cursor_color[0] - display_rgb[0]) > 1e-6f || fabsf(g->ui.cursor_color[1] - display_rgb[1]) > 1e-6f
        || fabsf(g->ui.cursor_color[2] - display_rgb[2]) > 1e-6f;
  if(!needs_rebuild) return;
 
  dt_drawlayer_ui_cursor_clear(&g->ui);
  g->ui.cursor_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, size_px, size_px);
  if(cairo_surface_status(g->ui.cursor_surface) != CAIRO_STATUS_SUCCESS)
  {
    dt_drawlayer_ui_cursor_clear(&g->ui);
    return;
  }
  cairo_surface_set_device_scale(g->ui.cursor_surface, ppd, ppd);
 
  unsigned char *data = cairo_image_surface_get_data(g->ui.cursor_surface);
  const int stride = cairo_image_surface_get_stride(g->ui.cursor_surface);
  memset(data, 0, (size_t)stride * size_px);
 
  dt_drawlayer_brush_dab_t dab = {
    .radius = fmaxf(widget_radius * (float)ppd, 0.5f),
    .shape = shape,
    .hardness = hardness,
    .opacity = opacity,
    .display_color = { display_rgb[0], display_rgb[1], display_rgb[2] },
  };
 
  const float half = 0.5f * (float)size_px;
  dt_drawlayer_brush_rasterize_dab_argb8(&dab, data, size_px, size_px, stride, half, half, 1.0f);
  cairo_surface_mark_dirty(g->ui.cursor_surface);
 
  g->ui.cursor_surface_size = size_px;
  g->ui.cursor_surface_ppd = ppd;
  g->ui.cursor_radius = widget_radius;
  g->ui.cursor_opacity = opacity;
  g->ui.cursor_hardness = hardness;
  g->ui.cursor_shape = shape;
  g->ui.cursor_color[0] = display_rgb[0];
  g->ui.cursor_color[1] = display_rgb[1];
  g->ui.cursor_color[2] = display_rgb[2];
}
 
static drawlayer_wait_dialog_t _show_drawlayer_wait_dialog(const char *title, const char *message)
{
  drawlayer_wait_dialog_t wait = { 0 };
  if(IS_NULL_PTR(dt_gui_get_global()) || IS_NULL_PTR(dt_gui_get_ui()) || IS_NULL_PTR(title) || !title[0] || IS_NULL_PTR(message) || !message[0]) return wait;
 
  GtkWidget *dialog = gtk_dialog_new();
  GtkWidget *main = dt_gui_main_window();
  if(main) gtk_window_set_transient_for(GTK_WINDOW(dialog), GTK_WINDOW(main));
  gtk_window_set_modal(GTK_WINDOW(dialog), TRUE);
  gtk_window_set_destroy_with_parent(GTK_WINDOW(dialog), TRUE);
  gtk_window_set_deletable(GTK_WINDOW(dialog), FALSE);
  gtk_window_set_resizable(GTK_WINDOW(dialog), FALSE);
  gtk_window_set_title(GTK_WINDOW(dialog), title);
  gtk_window_set_position(GTK_WINDOW(dialog), GTK_WIN_POS_CENTER_ON_PARENT);
 
  GtkWidget *content = gtk_dialog_get_content_area(GTK_DIALOG(dialog));
  GtkWidget *box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  GtkWidget *spinner = gtk_spinner_new();
  GtkWidget *label = gtk_label_new(message);
  gtk_label_set_xalign(GTK_LABEL(label), 0.0f);
  gtk_box_pack_start(GTK_BOX(box), spinner, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(box), label, TRUE, TRUE, 0);
  gtk_container_set_border_width(GTK_CONTAINER(box), DT_PIXEL_APPLY_DPI(12));
  gtk_box_pack_start(GTK_BOX(content), box, TRUE, TRUE, 0);
  gtk_spinner_start(GTK_SPINNER(spinner));
  gtk_widget_show_all(dialog);
  gtk_widget_show_now(dialog);
  gtk_window_present(GTK_WINDOW(dialog));
  GdkDisplay *display = gtk_widget_get_display(dialog);
  if(display) gdk_display_flush(display);
  /* `gui_focus()` / explicit sidecar save show this dialog and then immediately
   * enter synchronous worker-drain / TIFF-write code on the UI thread. Give GTK
   * a couple of non-blocking iterations so the modal maps and paints before that
   * blocking section starts, otherwise it may never become visible at all. */
  for(int k = 0; k < 2; k++)
    gtk_main_iteration_do(FALSE);
  wait.dialog = dialog;
  return wait;
}
 
typedef struct drawlayer_modal_wait_state_t
{
  GMainLoop *loop;
  const dt_iop_drawlayer_gui_data_t *g;
} drawlayer_modal_wait_state_t;
 
static gboolean _drawlayer_modal_wait_tick(gpointer user_data)
{
  drawlayer_modal_wait_state_t *state = (drawlayer_modal_wait_state_t *)user_data;
  if(IS_NULL_PTR(state) || IS_NULL_PTR(state->loop)) return G_SOURCE_REMOVE;
  if(!(state->g && dt_drawlayer_worker_any_active(state->g->stroke.worker)))
  {
    g_main_loop_quit(state->loop);
    return G_SOURCE_REMOVE;
  }
 
  return G_SOURCE_CONTINUE;
}
 
void dt_drawlayer_wait_for_rasterization_modal(const dt_iop_drawlayer_gui_data_t *g,
                                               const char *title, const char *message)
{
  if(!(g && dt_drawlayer_worker_any_active(g->stroke.worker))) return;
 
  drawlayer_wait_dialog_t wait = _show_drawlayer_wait_dialog(title, message);
  GMainLoop *loop = g_main_loop_new(NULL, FALSE);
  drawlayer_modal_wait_state_t state = {
    .loop = loop,
    .g = g,
  };
  const guint source_id = g_timeout_add(16, _drawlayer_modal_wait_tick, &state);
 
  if(g && dt_drawlayer_worker_any_active(g->stroke.worker))
    g_main_loop_run(loop);
 
  if(source_id) g_source_remove(source_id);
  if(wait.dialog)
  {
    gtk_widget_destroy(wait.dialog);
    wait.dialog = NULL;
  }
  g_main_loop_unref(loop);
}
 
static void _show_drawlayer_modal_message(const GtkMessageType type, const char *primary, const char *secondary)
{
  if(IS_NULL_PTR(dt_gui_get_global()) || IS_NULL_PTR(dt_gui_get_ui()) || IS_NULL_PTR(primary) || primary[0] == '\0') return;
 
  GtkWidget *dialog = gtk_message_dialog_new(GTK_WINDOW(dt_gui_main_window()),
                                             GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_MODAL,
                                             type, GTK_BUTTONS_OK, "%s", primary);
  if(secondary && secondary[0] != '\0')
    gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(dialog), "%s", secondary);
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}
 
static gboolean _prompt_layer_name_dialog(const char *title, const char *message, const char *initial_name,
                                          char *name, const size_t name_size)
{
  if(IS_NULL_PTR(dt_gui_get_global()) || IS_NULL_PTR(dt_gui_get_ui()) || IS_NULL_PTR(title) || title[0] == '\0' || IS_NULL_PTR(name) || name_size == 0) return FALSE;
 
  GtkWidget *dialog = gtk_dialog_new_with_buttons(
      title, GTK_WINDOW(dt_gui_main_window()),
      GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_MODAL, _("Cancel"), GTK_RESPONSE_CANCEL,
      _("Confirm"), GTK_RESPONSE_ACCEPT, NULL);
  GtkWidget *content = gtk_dialog_get_content_area(GTK_DIALOG(dialog));
  GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  GtkWidget *entry = gtk_entry_new();
  if(!IS_NULL_PTR(message) && message[0] != '\0')
  {
    GtkWidget *label = gtk_label_new(message);
    gtk_label_set_xalign(GTK_LABEL(label), 0.0f);
    gtk_label_set_line_wrap(GTK_LABEL(label), TRUE);
    gtk_box_pack_start(GTK_BOX(box), label, FALSE, FALSE, 0);
  }
  gtk_entry_set_activates_default(GTK_ENTRY(entry), TRUE);
  if(initial_name && initial_name[0] != '\0') gtk_entry_set_text(GTK_ENTRY(entry), initial_name);
  gtk_box_pack_start(GTK_BOX(box), entry, FALSE, FALSE, 0);
  gtk_container_set_border_width(GTK_CONTAINER(box), DT_PIXEL_APPLY_DPI(12));
  gtk_box_pack_start(GTK_BOX(content), box, TRUE, TRUE, 0);
  gtk_dialog_set_default_response(GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT);
  gtk_widget_show_all(dialog);
 
  gboolean accepted = FALSE;
  if(gtk_dialog_run(GTK_DIALOG(dialog)) == GTK_RESPONSE_ACCEPT)
  {
    _sanitize_requested_layer_name(gtk_entry_get_text(GTK_ENTRY(entry)), name, name_size);
    accepted = _layer_name_non_empty(name);
  }
 
  gtk_widget_destroy(dialog);
  return accepted;
}
 
static gboolean _color_picker_set_from_position(dt_iop_module_t *self, const float x, const float y)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets || IS_NULL_PTR(g->controls.color)) return FALSE;
 
  float display_rgb[3] = { 0.0f };
  if(!dt_drawlayer_widgets_update_from_picker_position(g->ui.widgets, g->controls.color, x, y, display_rgb)) return FALSE;
  _apply_display_brush_color(self, display_rgb, FALSE);
  return TRUE;
}
 
static gboolean _color_picker_draw(GtkWidget *widget, cairo_t *cr, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets) return FALSE;
  const double ppd = (dt_gui_get_global() && dt_gui_get_global()->ppd > 0.0) ? dt_gui_get_global()->ppd : 1.0;
  return dt_drawlayer_widgets_draw_picker(g->ui.widgets, widget, cr, ppd);
}
 
static gboolean _color_swatch_draw(GtkWidget *widget, cairo_t *cr, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets) return FALSE;
  return dt_drawlayer_widgets_draw_swatch(g->ui.widgets, widget, cr);
}
 
static gboolean _color_swatch_button_press(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets || !widget || IS_NULL_PTR(event) || event->button != 1) return FALSE;
 
  float display_rgb[3] = { 0.0f };
  if(!dt_drawlayer_widgets_pick_history_color(g->ui.widgets, widget, event->x, event->y, display_rgb)) return FALSE;
  _apply_display_brush_color(self, display_rgb, FALSE);
  return TRUE;
}
 
static void _sync_brush_profile_preview_widget(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets || IS_NULL_PTR(g->controls.brush_shape)) return;
 
  dt_drawlayer_widgets_set_brush_profile_preview(g->ui.widgets, _conf_opacity() / 100.0f, _conf_hardness(),
                                                 _conf_sprinkles() / 100.0f, _conf_sprinkle_size(),
                                                 _conf_sprinkle_coarseness() / 100.0f, _conf_brush_shape());
  gtk_widget_queue_draw(g->controls.brush_shape);
}
 
static gboolean _brush_profile_draw(GtkWidget *widget, cairo_t *cr, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets) return FALSE;
  const double ppd = (dt_gui_get_global() && dt_gui_get_global()->ppd > 0.0) ? dt_gui_get_global()->ppd : 1.0;
  return dt_drawlayer_widgets_draw_brush_profiles(g->ui.widgets, widget, cr, ppd);
}
 
static gboolean _brush_profile_button_press(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || !g->ui.widgets || !widget || IS_NULL_PTR(event) || event->button != 1) return FALSE;
 
  int shape = DT_DRAWLAYER_BRUSH_SHAPE_LINEAR;
  if(!dt_drawlayer_widgets_pick_brush_profile(g->ui.widgets, widget, event->x, event->y, &shape)) return FALSE;
 
  _sync_params_from_gui(self, FALSE);
  _sync_mode_sensitive_widgets(self);
  if(!_update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, TRUE).ok) return FALSE;
  _sync_brush_profile_preview_widget(self);
  gtk_widget_queue_draw(widget);
  return TRUE;
}
 
static gboolean _working_rgb_to_display_rgb(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe,
                                            const float working_rgb[3], float display_rgb[3])
{
  if(IS_NULL_PTR(working_rgb) || !display_rgb) return FALSE;
 
  const float gain = exp2f(_conf_hdr_exposure());
  const float inv_gain = (gain > 0.0f) ? 1.0f / gain : 1.0f;
  const float preview_rgb[3] = {
    working_rgb[0] * inv_gain,
    working_rgb[1] * inv_gain,
    working_rgb[2] * inv_gain,
  };
 
  display_rgb[0] = _clamp01(preview_rgb[0]);
  display_rgb[1] = _clamp01(preview_rgb[1]);
  display_rgb[2] = _clamp01(preview_rgb[2]);
 
  if(IS_NULL_PTR(self) || IS_NULL_PTR(pipe)) return TRUE;
 
  const dt_iop_order_iccprofile_info_t *const work_profile
      = self->dev ? dt_ioppr_get_iop_work_profile_info(self, self->dev->iop) : NULL;
  const dt_iop_order_iccprofile_info_t *const display_profile = dt_ioppr_get_pipe_output_profile_info(pipe);
  if(IS_NULL_PTR(work_profile) || !display_profile) return TRUE;
 
  float in[4] = { preview_rgb[0], preview_rgb[1], preview_rgb[2], 0.0f };
  float out[4] = { preview_rgb[0], preview_rgb[1], preview_rgb[2], 0.0f };
  dt_ioppr_transform_image_colorspace_rgb(in, out, 1, 1, work_profile, display_profile, "drawlayer picked color");
  display_rgb[0] = _clamp01(out[0]);
  display_rgb[1] = _clamp01(out[1]);
  display_rgb[2] = _clamp01(out[2]);
  return TRUE;
}
 
void color_picker_apply(dt_iop_module_t *self, GtkWidget *picker, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  (void)picker;
  (void)piece;
  if(IS_NULL_PTR(self) || dt_gui_widgets_suppressed()) return;
  const drawlayer_pick_source_t source = _conf_pick_source();
  const float *picked = (source == DRAWLAYER_PICK_SOURCE_OUTPUT) ? self->picked_output_color : self->picked_color;
  const float *picked_min
      = (source == DRAWLAYER_PICK_SOURCE_OUTPUT) ? self->picked_output_color_min : self->picked_color_min;
  const float *picked_max
      = (source == DRAWLAYER_PICK_SOURCE_OUTPUT) ? self->picked_output_color_max : self->picked_color_max;
  if(picked_max[0] < picked_min[0]) return;
 
  float display_rgb[3] = { 0.0f };
  if(!_working_rgb_to_display_rgb(self, pipe, picked, display_rgb)) return;
  _apply_display_brush_color(self, display_rgb, TRUE);
}
 
static gboolean _color_picker_button_press(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(IS_NULL_PTR(event) || event->button != 1) return FALSE;
  (void)widget;
  return _color_picker_set_from_position(self, event->x, event->y);
}
 
static gboolean _color_picker_button_release(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  (void)widget;
  (void)event;
  if(!IS_NULL_PTR(g) && g->ui.widgets)
  {
    float display_rgb[3] = { 0.0f };
    if(dt_drawlayer_widgets_finish_picker_drag(g->ui.widgets, display_rgb))
      _remember_display_color(self, display_rgb);
  }
  return FALSE;
}
 
static gboolean _color_picker_motion(GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  (void)widget;
  if(IS_NULL_PTR(g) || !g->ui.widgets || IS_NULL_PTR(event) || !dt_drawlayer_widgets_is_picker_dragging(g->ui.widgets)) return FALSE;
  return _color_picker_set_from_position(self, event->x, event->y);
}
 
static void _sanitize_params(dt_iop_module_t *self, dt_iop_drawlayer_params_t *params)
{
  if(IS_NULL_PTR(params)) return;
 
  if(memchr(params->layer_name, '\0', sizeof(params->layer_name)) == NULL)
    memset(params->layer_name, 0, sizeof(params->layer_name));
  else
    params->layer_name[sizeof(params->layer_name) - 1] = '\0';
 
  char sanitized_layer_name[DRAWLAYER_NAME_SIZE] = { 0 };
  _sanitize_requested_layer_name(params->layer_name, sanitized_layer_name, sizeof(sanitized_layer_name));
  if(g_strcmp0(params->layer_name, sanitized_layer_name))
    g_strlcpy(params->layer_name, sanitized_layer_name, sizeof(params->layer_name));
 
  if(memchr(params->work_profile, '\0', sizeof(params->work_profile)) == NULL)
    memset(params->work_profile, 0, sizeof(params->work_profile));
  else
    params->work_profile[sizeof(params->work_profile) - 1] = '\0';
 
  if(!_layer_name_non_empty(params->layer_name))
  {
    params->layer_name[0] = '\0';
    params->layer_order = -1;
    params->sidecar_timestamp = 0;
  }
  if(params->layer_order < -1) params->layer_order = -1;
  if(params->work_profile[0] != '\0' && !_profile_key_is_sane(params->work_profile))
    memset(params->work_profile, 0, sizeof(params->work_profile));
 
  // Freshly enabled or migrated instances without a concrete sidecar page should adopt the current profile.
  if(params->layer_order < 0 && params->stroke_commit_hash == 0u)
    memset(params->work_profile, 0, sizeof(params->work_profile));
 
  if(params->work_profile[0] == '\0' && !IS_NULL_PTR(self) && self->dev)
  {
    char current_profile[DRAWLAYER_PROFILE_SIZE] = { 0 };
    if(_get_current_work_profile_key(self, self->dev->iop, self->dev->pipe, current_profile,
                                     sizeof(current_profile)))
      g_strlcpy(params->work_profile, current_profile, sizeof(params->work_profile));
  }
}
 
static void _sanitize_requested_layer_name(const char *requested, char *name, const size_t name_size)
{
  if(IS_NULL_PTR(name) || name_size == 0) return;
  name[0] = '\0';
  if(!(!IS_NULL_PTR(requested) && requested[0])) return;
 
  gboolean last_was_space = FALSE;
  size_t out = 0;
  for(size_t in = 0; requested[in] != '\0' && out + 1 < name_size; in++)
  {
    const unsigned char ch = (unsigned char)requested[in];
    if(g_ascii_isspace(ch))
    {
      if(out > 0 && !last_was_space)
      {
        name[out++] = ' ';
        last_was_space = TRUE;
      }
      continue;
    }
 
    name[out++] = (char)ch;
    last_was_space = FALSE;
  }
  name[out] = '\0';
  g_strstrip(name);
}
 
/* Realtime worker/queue implementation lives in its own implementation include. */
#include "drawlayer/worker.c"
 
/* Layer cache and sidecar synchronization stay in a private implementation
 * include so drawlayer.c keeps the orchestration flow readable without
 * introducing a second public API boundary. */
#include "drawlayer/layers.c"
 
// Find the cached working layer if any
static inline __attribute__((always_inline)) gboolean _update_runtime_state(const drawlayer_runtime_request_t *request,
                                      dt_drawlayer_runtime_source_t *source)
{
  if(source) *source = (dt_drawlayer_runtime_source_t){ 0 };
  if(IS_NULL_PTR(request) || IS_NULL_PTR(request->self) || IS_NULL_PTR(request->piece) || IS_NULL_PTR(request->pipe) || IS_NULL_PTR(request->roi_out)
     || !request->runtime_params || !source)
    return FALSE;
 
  const dt_dev_pixelpipe_t *const pipe = request->pipe;
  dt_drawlayer_runtime_manager_t *const manager = request->manager;
  dt_drawlayer_process_state_t *const process = request->process_state;
 
  if(process && process->cache_valid && process->base_patch.pixels && process->cache_imgid == pipe->dev->image_storage.id)
  {
    dt_iop_roi_t process_roi = request->roi_out ? *request->roi_out : *request->roi_in;
    const dt_iop_roi_t source_full_roi = {
      .x = 0,
      .y = 0,
      .width = process->base_patch.width,
      .height = process->base_patch.height,
      .scale = 1.0f,
    };
 
    /* The canvas has the raw image's dimensions and this module's frame is a window into it, at
     * the position the size fold gives that window (piece->buf_in.x/y -- a crop records itself
     * there). So the window this render reads is the requested output window shifted by that
     * origin -- and by nothing else. No scale: canvas and frame share the pixel pitch. No
     * rotation: the flip is already in the canvas's orientation.
     *
     * dt_interpolation_resample() reads source pixel ((x + i) / scale) for output column i, and
     * target_roi->x is in those same scaled units, which is why the offset is multiplied by the
     * render's own scale here and by nothing else.
     *
     * Before this the canvas WAS the module's frame and target_roi indexed it directly -- so the
     * canvas changed size with every crop and the authored raster was re-fitted onto the new
     * frame. The paint moved and stretched with the crop; that is the bug this fixes.
     *
     * KNOWN LIMIT: when the frame is LARGER than the canvas (a perspective correction expands it)
     * the offset goes negative and the resampler clamps to the canvas edge instead of reading
     * transparency, so paint touching the very edge of the canvas smears outward into the added
     * margin. Paint that does not reach the edge is unaffected. */
    dt_drawlayer_raw_placement_t placement;
    if(dt_drawlayer_raw_placement_for_frame(request->self, pipe, &request->piece->buf_in, &placement))
    {
      process_roi.x += (int)lroundf((float)placement.offset_x * process_roi.scale);
      process_roi.y += (int)lroundf((float)placement.offset_y * process_roi.scale);
    }
    source->kind = DT_DRAWLAYER_SOURCE_BASE_PATCH;
    source->pixels = process->base_patch.pixels;
    source->cache_entry = process->base_patch.cache_entry;
    source->width = process->base_patch.width;
    source->height = process->base_patch.height;
    source->direct_copy = FALSE;
    source->source_roi = source_full_roi;
    source->target_roi = process_roi;
    dt_drawlayer_cache_patch_rdlock(&process->base_patch);
    if(manager)
    {
      source->tracked_buffer = DT_DRAWLAYER_RUNTIME_BUFFER_BASE_PATCH;
      source->tracked_actor = request->use_opencl ? DT_DRAWLAYER_RUNTIME_ACTOR_PIPELINE_CL
                                                  : DT_DRAWLAYER_RUNTIME_ACTOR_PIPELINE_CPU;
      source->tracked_read_lock = TRUE;
      dt_drawlayer_runtime_manager_note_buffer_lock(manager, source->tracked_buffer, source->tracked_actor, FALSE,
                                                    TRUE);
    }
    return TRUE;
  }
 
  return FALSE;
}
 
static inline __attribute__((always_inline)) drawlayer_preview_background_t _resolve_preview_background(const dt_iop_module_t *self,
                                                                  const dt_iop_drawlayer_gui_data_t *gui)
{
  const int preview_mode = (gui && self && self->dev && self->dev->gui_module == self)
                               ? gui->session.preview_bg_mode
                               : DRAWLAYER_PREVIEW_BG_IMAGE;
  return (drawlayer_preview_background_t){
    .enabled = (preview_mode != DRAWLAYER_PREVIEW_BG_IMAGE),
    .value = (preview_mode == DRAWLAYER_PREVIEW_BG_WHITE)  ? 1.0f
           : (preview_mode == DRAWLAYER_PREVIEW_BG_GREY) ? 0.5f
                                                         : 0.0f,
  };
}
 
void dt_drawlayer_touch_stroke_commit_hash(dt_iop_drawlayer_params_t *params, const int dab_count,
                                           const gboolean have_last_dab, const float last_dab_x,
                                           const float last_dab_y, const uint32_t publish_serial)
{
  if(IS_NULL_PTR(params)) return;
 
  uint32_t x_bits = 0u;
  uint32_t y_bits = 0u;
  if(have_last_dab)
  {
    memcpy(&x_bits, &last_dab_x, sizeof(x_bits));
    memcpy(&y_bits, &last_dab_y, sizeof(y_bits));
  }
 
  const uint32_t seed[5] = { (uint32_t)dab_count, have_last_dab ? 1u : 0u, x_bits, y_bits, publish_serial };
 
  uint64_t hash = params->stroke_commit_hash ? params->stroke_commit_hash : 5381u;
  hash = dt_hash(hash, (const char *)seed, sizeof(seed));
 
  /* Keep the serialized field non-zero so "uninitialized" remains distinguishable
   * from "updated at least once" in legacy parameter blobs. */
  params->stroke_commit_hash = (uint32_t)(hash ? hash : 1u);
}
 
static void _refresh_layer_widgets(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  GMainContext *const ui_ctx = g_main_context_default();
  if(IS_NULL_PTR(g) || IS_NULL_PTR(params) || !(ui_ctx && g_main_context_is_owner(ui_ctx))) return;
 
  g->manager.background_job_running = g->session.background_job_running;
 
  if(g->controls.layer_select) _populate_layer_list(self);
  _sync_layer_controls(self);
}
 
static void _sync_layer_controls(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(params)) return;
 
  const gboolean attached = _layer_name_non_empty(params->layer_name);
  const gboolean missing = (g->session.missing_layer_error[0] != '\0');
  const gboolean have_existing_layers = g->controls.layer_select && dt_bauhaus_combobox_length(g->controls.layer_select) > 0;
 
  if(g->controls.notebook)
  {
    if(g->controls.brush_tab) gtk_widget_set_visible(g->controls.brush_tab, attached);
    if(g->controls.input_tab) gtk_widget_set_visible(g->controls.input_tab, attached);
    if(g->controls.layer_tab) gtk_widget_set_visible(g->controls.layer_tab, TRUE);
    gtk_notebook_set_show_tabs(GTK_NOTEBOOK(g->controls.notebook), attached);
    gtk_notebook_set_show_border(GTK_NOTEBOOK(g->controls.notebook), attached);
    if(!attached && g->controls.layer_tab)
      gtk_notebook_set_current_page(GTK_NOTEBOOK(g->controls.notebook),
                                    gtk_notebook_page_num(GTK_NOTEBOOK(g->controls.notebook), g->controls.layer_tab));
  }
 
  if(g->controls.preview_title) gtk_widget_set_visible(g->controls.preview_title, attached);
  if(g->controls.preview_box) gtk_widget_set_visible(g->controls.preview_box, attached);
  if(g->controls.layer_action_row) gtk_widget_set_visible(g->controls.layer_action_row, TRUE);
  if(g->controls.layer_status)
  {
    gtk_label_set_text(GTK_LABEL(g->controls.layer_status), missing ? g->session.missing_layer_error : "");
    gtk_widget_set_visible(g->controls.layer_status, missing);
  }
  if(g->controls.delete_layer) gtk_widget_set_visible(g->controls.delete_layer, attached);
  if(g->controls.rename_layer) gtk_widget_set_visible(g->controls.rename_layer, attached);
  if(g->controls.layer_fill_title) gtk_widget_set_visible(g->controls.layer_fill_title, attached);
  if(g->controls.layer_fill_row) gtk_widget_set_visible(g->controls.layer_fill_row, attached);
  if(g->controls.create_background) gtk_widget_set_visible(g->controls.create_background, attached);
  if(g->controls.save_layer) gtk_widget_set_visible(g->controls.save_layer, attached);
  if(g->controls.attach_layer) gtk_widget_set_visible(g->controls.attach_layer, !attached && have_existing_layers);
 
  if(g->controls.layer_select) gtk_widget_set_visible(g->controls.layer_select, attached || have_existing_layers);
  if(g->controls.create_layer) gtk_widget_set_sensitive(g->controls.create_layer, TRUE);
  if(g->controls.rename_layer) gtk_widget_set_sensitive(g->controls.rename_layer, attached);
  if(g->controls.attach_layer) gtk_widget_set_sensitive(g->controls.attach_layer, have_existing_layers);
  if(g->controls.create_background)
    gtk_widget_set_sensitive(g->controls.create_background, attached && !g->session.background_job_running);
  if(g->controls.save_layer) gtk_widget_set_sensitive(g->controls.save_layer, attached);
}
 
static void _sync_preview_bg_buttons(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g)) return;
 
  if(GTK_IS_TOGGLE_BUTTON(g->controls.preview_bg_image))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.preview_bg_image),
                                 g->session.preview_bg_mode == DRAWLAYER_PREVIEW_BG_IMAGE);
  if(GTK_IS_TOGGLE_BUTTON(g->controls.preview_bg_white))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.preview_bg_white),
                                 g->session.preview_bg_mode == DRAWLAYER_PREVIEW_BG_WHITE);
  if(GTK_IS_TOGGLE_BUTTON(g->controls.preview_bg_grey))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.preview_bg_grey),
                                 g->session.preview_bg_mode == DRAWLAYER_PREVIEW_BG_GREY);
  if(GTK_IS_TOGGLE_BUTTON(g->controls.preview_bg_black))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.preview_bg_black),
                                 g->session.preview_bg_mode == DRAWLAYER_PREVIEW_BG_BLACK);
}
 
gboolean dt_drawlayer_commit_dabs(dt_iop_module_t *self, const gboolean record_history)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev)) return TRUE;
  /* A stroke is still physically in progress (button held down). Never finalize or
   * reset it here — that would truncate the live path. This must guard BOTH commit
   * kinds: a quiet flush (record_history == FALSE, scheduled by GUI_SCROLL /
   * GUI_SYNC_TEMP_BUFFERS while pending stroke work exists) would otherwise run
   * _wait_worker_idle + finalize + _reset_stroke_session mid-stroke without ever
   * clearing painting_active, silently cutting the stroke short. The realtime worker
   * already keeps base_patch updated incrementally, so there is nothing to flush
   * mid-stroke; defer a history commit to the worker and no-op a quiet flush. The
   * real commit runs on STROKE_END / focus-loss / image-change, where
   * _apply_runtime_event() has already cleared painting_active first. */
  if(g->manager.painting_active)
  {
    if(record_history) dt_drawlayer_worker_request_commit(g->stroke.worker);
    dt_print(DT_DEBUG_PERF, "[drawlayer] commit_dabs deferred: stroke in progress (record_history=%d)\n",
             record_history);
    return TRUE;
  }
 
  _cancel_async_commit(g->stroke.worker);
 
  if(!record_history)
    dt_drawlayer_worker_seal_for_commit(g->stroke.worker);
 
  /* Commit ordering is strict:
   * - the backend worker must be idle,
   * - the full-resolution layer cache must already contain the stroke,
   * - only then do we mutate params/history so the pipeline invalidation sees a coherent state. */
  _wait_worker_idle(self, g->stroke.worker);
  /* Damage-rectangle ownership stays in drawlayer:
   * paint accumulates per-dab bounds into a stroke rectangle, and on commit the
   * module consumes that rectangle to update cache dirty state. */
  dt_drawlayer_worker_publish_backend_stroke_damage(self);
 
  int sample_count = 0;
  gboolean had_stroke = FALSE;
  gboolean had_last_dab = FALSE;
  float last_dab_x = 0.0f;
  float last_dab_y = 0.0f;
  dt_iop_gui_enter_critical_section(self);
  g->stroke.finish_commit_pending = FALSE;
  sample_count = (int)g->stroke.stroke_sample_count;
  had_stroke = (sample_count > 0);
  had_last_dab = g->stroke.last_dab_valid;
  last_dab_x = g->stroke.last_dab_x;
  last_dab_y = g->stroke.last_dab_y;
  _reset_stroke_session(g);
  dt_iop_gui_leave_critical_section(self);
  dt_drawlayer_worker_reset_stroke(g->stroke.worker);
 
  if(had_stroke)
  {
    /* Keep stroke commit lightweight for interactive rendering:
     * - do not flush process tile back to base patch here,
     * - do not invalidate the process tile here.
     *
     * Base-patch synchronization is handled at explicit persistence points
     * (save/focus-out/mouse-leave/geometry rebuild) so recomputes can keep
     * blending the already-updated process tile directly. */
    _touch_stroke_commit_hash(params, sample_count, had_last_dab, last_dab_x, last_dab_y, 0u);
    _retain_base_patch_stroke_ref(g);
    if(record_history && self->dev)
    {
      dt_dev_undo_start_record(self->dev);
      dt_pthread_rwlock_wrlock(&self->dev->history_mutex);
      dt_dev_add_history_item_ext(self->dev, self, TRUE, FALSE);
      dt_dev_set_history_hash(self->dev, dt_dev_history_compute_hash(self->dev));
      dt_pthread_rwlock_unlock(&self->dev->history_mutex);
      dt_dev_undo_end_record(self->dev);
      if(self->post_history_commit) self->post_history_commit(self);
 
      g->manager.realtime_active = FALSE;
      _set_drawlayer_pipeline_realtime_mode(self, FALSE);
      dt_dev_pixelpipe_update_history_all(self->dev);
      dt_dev_write_history(self->dev, FALSE);
      dt_dev_history_notify_change(self->dev, self->dev->image_storage.id);
    }
 
    /* The final stroke-end raster batches may land after the button-release
     * event already requested one redraw. Queue one more redraw now that the
     * worker is idle and the last published process snapshot is coherent, so
     * late-finishing strokes become visible even without further UI activity. */
    if(self->dev && self->dev->gui_attached) dt_control_queue_redraw_center();
  }
 
  if(!(had_stroke && record_history))
  {
    g->manager.realtime_active = FALSE;
    _set_drawlayer_pipeline_realtime_mode(self, FALSE);
  }
 
  return TRUE;
}
 
static void _develop_ui_pipe_finished_callback(gpointer instance, gpointer user_data)
{
  (void)instance;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev)) return;
  drawlayer_runtime_host_context_t runtime_host = {
    .runtime = {
      .self = self,
      .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
      .gui = g,
      .manager = &g->manager,
      .process_state = &g->process,
    },
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = &runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  dt_drawlayer_runtime_manager_update(
      &g->manager,
      &(dt_drawlayer_runtime_update_request_t){
        .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_PIPE_FINISHED,
        .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
      },
      &runtime_manager);
}
 
static void _sync_mode_sensitive_widgets(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(g->controls.color) || IS_NULL_PTR(g->controls.softness)) return;
 
  const gboolean paint_mode = (_conf_brush_mode() == DT_DRAWLAYER_BRUSH_MODE_PAINT);
  const gboolean show_hardness = (_conf_brush_shape() != DT_DRAWLAYER_BRUSH_SHAPE_GAUSSIAN);
  gtk_widget_set_visible(GTK_WIDGET(g->controls.color), paint_mode);
  if(g->controls.color_row) gtk_widget_set_visible(g->controls.color_row, paint_mode);
  if(g->controls.color_swatch) gtk_widget_set_visible(g->controls.color_swatch, paint_mode);
  if(g->controls.image_colorpicker) gtk_widget_set_visible(g->controls.image_colorpicker, paint_mode);
  if(g->controls.image_colorpicker_source) gtk_widget_set_visible(g->controls.image_colorpicker_source, paint_mode);
  gtk_widget_set_visible(g->controls.softness, show_hardness);
}
 
static gboolean _delete_current_layer(dt_iop_module_t *self)
{
  if(IS_NULL_PTR(self->dev)) return FALSE;
 
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(!_layer_name_non_empty(params->layer_name)) return FALSE;
 
  GString *errors = g_string_new(NULL);
  gboolean deleted = FALSE;
  int layer_width = 0;
  int layer_height = 0;
  if(!_resolve_layer_geometry(self, NULL, NULL, &layer_width, &layer_height, NULL, NULL))
  {
    const dt_dev_image_geometry_t geometry = dt_dev_geometry_snapshot(self->dev);
    layer_width = geometry.raw_width;
    layer_height = geometry.raw_height;
  }
 
  char path[DT_PATH_MAX] = { 0 };
  if(!dt_drawlayer_io_sidecar_path(self->dev->image_storage.id, path, sizeof(path)))
  {
    _layerio_append_error(errors, _("failed to resolve drawlayer sidecar path"));
  }
  else if(!g_file_test(path, G_FILE_TEST_EXISTS))
  {
    _layerio_append_error(errors, _("drawlayer sidecar TIFF is missing"));
  }
  else
  {
    if(!dt_drawlayer_io_delete_layer(path, params->layer_name, layer_width, layer_height))
      _layerio_append_error(errors, _("failed to delete drawing layer from sidecar"));
    else
    {
      deleted = TRUE;
      params->layer_name[0] = '\0';
      params->layer_order = -1;
      params->sidecar_timestamp = 0;
      memset(params->work_profile, 0, sizeof(params->work_profile));
      if(g) g->session.missing_layer_error[0] = '\0';
      if(!IS_NULL_PTR(g))
      {
        _release_all_base_patch_extra_refs(g);
        dt_drawlayer_cache_patch_clear(&g->process.base_patch, "drawlayer patch");
        g->process.cache_valid = FALSE;
        g->process.cache_dirty = FALSE;
        dt_drawlayer_paint_runtime_state_reset(&g->process.cache_dirty_rect);
        g->process.cache_imgid = -1;
        g->process.cache_layer_name[0] = '\0';
        g->process.cache_layer_order = -1;
        _reset_stroke_session(g);
      }
      _refresh_layer_widgets(self);
    }
  }
 
  _layerio_log_errors(errors);
  g_string_free(errors, TRUE);
  return deleted;
}
 
static gboolean _confirm_delete_layer(dt_iop_module_t *self, const gboolean removing_module)
{
  if(IS_NULL_PTR(self->dev)) return FALSE;
 
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(!_layer_name_non_empty(params->layer_name)) return removing_module;
 
  GtkWidget *dialog = gtk_message_dialog_new(
      GTK_WINDOW(dt_gui_main_window()), GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_MODAL,
      GTK_MESSAGE_QUESTION, GTK_BUTTONS_NONE, "%s",
      removing_module
          ? _("Delete the linked drawing layer from the sidecar TIFF before removing this module instance?")
          : _("Delete the linked drawing layer from the sidecar TIFF?"));
  if(removing_module)
  {
    gtk_dialog_add_button(GTK_DIALOG(dialog), _("Keep layer"), GTK_RESPONSE_NO);
    gtk_dialog_add_button(GTK_DIALOG(dialog), _("Delete layer"), GTK_RESPONSE_YES);
  }
  else
  {
    gtk_dialog_add_button(GTK_DIALOG(dialog), _("Cancel"), GTK_RESPONSE_CANCEL);
    gtk_dialog_add_button(GTK_DIALOG(dialog), _("Delete"), GTK_RESPONSE_ACCEPT);
  }
 
  const int response = gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
 
  if(removing_module)
  {
    if(response == GTK_RESPONSE_YES) _delete_current_layer(self);
    /* Module removal must proceed regardless of the answer or any layer-delete failure. */
    return TRUE;
  }
 
  if(response != GTK_RESPONSE_ACCEPT) return FALSE;
  return _delete_current_layer(self);
}
 
static gboolean _rename_current_layer_from_gui(dt_iop_module_t *self, const char *requested_name)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return FALSE;
  if(!_layer_name_non_empty(params->layer_name)) return FALSE;
 
  char new_name[DRAWLAYER_NAME_SIZE] = { 0 };
  char stripped_requested[DRAWLAYER_NAME_SIZE] = { 0 };
  if(!IS_NULL_PTR(requested_name)) g_strlcpy(stripped_requested, requested_name, sizeof(stripped_requested));
  g_strstrip(stripped_requested);
  if(stripped_requested[0] == '\0') return FALSE;
  _sanitize_requested_layer_name(requested_name, new_name, sizeof(new_name));
  if(new_name[0] == '\0') return FALSE;
 
  if(!g_strcmp0(new_name, params->layer_name)) return TRUE;
 
  GString *errors = g_string_new(NULL);
  gboolean renamed = FALSE;
  int layer_width = 0;
  int layer_height = 0;
  if(!_resolve_layer_geometry(self, NULL, NULL, &layer_width, &layer_height, NULL, NULL))
  {
    const dt_dev_image_geometry_t geometry = dt_dev_geometry_snapshot(self->dev);
    layer_width = geometry.raw_width;
    layer_height = geometry.raw_height;
  }
 
  if(!_commit_dabs(self, FALSE))
    _layerio_append_error(errors, _("failed to commit drawing stroke before renaming"));
  else if(!_flush_layer_cache(self))
    _layerio_append_error(errors, _("failed to write drawing layer sidecar"));
  else
  {
    char path[DT_PATH_MAX] = { 0 };
    if(!dt_drawlayer_io_sidecar_path(self->dev->image_storage.id, path, sizeof(path)))
      _layerio_append_error(errors, _("failed to resolve drawlayer sidecar path"));
    else if(!g_file_test(path, G_FILE_TEST_EXISTS))
      _layerio_append_error(errors, _("drawlayer sidecar TIFF is missing"));
    else
    {
      dt_drawlayer_io_layer_info_t info = { 0 };
      if(!dt_drawlayer_io_rename_layer(path, params->layer_name, new_name, params->work_profile,
                                       layer_width, layer_height, &info))
        _layerio_append_error(errors, _("failed to rename drawing layer in sidecar"));
      else
      {
        g_strlcpy(params->layer_name, new_name, sizeof(params->layer_name));
        params->layer_order = info.index;
        params->sidecar_timestamp = _sidecar_timestamp_from_path(path);
        g_strlcpy(g->process.cache_layer_name, params->layer_name, sizeof(g->process.cache_layer_name));
        g->process.cache_layer_order = params->layer_order;
        renamed = TRUE;
      }
    }
  }
 
  if(renamed)
  {
    g->session.missing_layer_error[0] = '\0';
    _refresh_layer_widgets(self);
    if(self->dev) dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  }
  else
  {
    _refresh_layer_widgets(self);
  }
 
  _layerio_log_errors(errors);
  g_string_free(errors, TRUE);
  return renamed;
}
 
static gboolean _create_new_layer(dt_iop_module_t *self, const char *requested_name)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return FALSE;
 
  char new_name[DRAWLAYER_NAME_SIZE] = { 0 };
  char stripped_requested[DRAWLAYER_NAME_SIZE] = { 0 };
  if(!IS_NULL_PTR(requested_name)) g_strlcpy(stripped_requested, requested_name, sizeof(stripped_requested));
  g_strstrip(stripped_requested);
  if(stripped_requested[0] == '\0') return FALSE;
  _sanitize_requested_layer_name(requested_name, new_name, sizeof(new_name));
  if(new_name[0] == '\0') return FALSE;
 
  char path[DT_PATH_MAX] = { 0 };
  if(dt_drawlayer_io_sidecar_path(self->dev->image_storage.id, path, sizeof(path))
     && dt_drawlayer_io_layer_name_exists(path, new_name, -1))
  {
    _show_drawlayer_modal_message(GTK_MESSAGE_ERROR,
                                  _("A drawing layer with that name already exists."),
                                  _("Choose a different layer name."));
    return FALSE;
  }
 
  const dt_iop_drawlayer_params_t previous = *params;
 
  if(!_commit_dabs(self, FALSE)) return FALSE;
  if(!_flush_layer_cache(self)) return FALSE;
 
  g_strlcpy(params->layer_name, new_name, sizeof(params->layer_name));
  params->layer_order = -1;
  params->sidecar_timestamp = 0;
  memset(params->work_profile, 0, sizeof(params->work_profile));
 
  if(!_update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, FALSE).ok)
  {
    *params = previous;
    gui_update(self);
    return FALSE;
  }
 
  /* Creating a layer must materialize it in the TIFF immediately so the
   * shared combobox only ever lists real on-disk layers and drawing can start
   * on the same authoritative cache line without a later bootstrap step. */
  if(!g->process.cache_valid || IS_NULL_PTR(g->process.base_patch.pixels))
  {
    *params = previous;
    gui_update(self);
    return FALSE;
  }
  g->process.cache_dirty = TRUE;
  if(!_flush_layer_cache(self))
  {
    *params = previous;
    gui_update(self);
    return FALSE;
  }
 
  g->session.missing_layer_error[0] = '\0';
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  if(self->dev)
  {
    dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
    dt_dev_pixelpipe_update_history_all(self->dev);
  }
  _refresh_layer_widgets(self);
  gui_update(self);
  return TRUE;
}
 
static void _build_pre_module_filter_string(dt_iop_module_t *self, char *filter, const size_t filter_size)
{
  if(IS_NULL_PTR(filter) || filter_size == 0) return;
  filter[0] = '\0';
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(self->dev->pipe)) return;
 
  dt_dev_pixelpipe_iop_t *self_piece = dt_dev_distort_get_iop_pipe(self->dev->pipe, self);
  const char *prev_op = NULL;
  if(self_piece && self->dev->pipe)
  {
    for(GList *nodes = self->dev->pipe->nodes; nodes; nodes = g_list_next(nodes))
    {
      dt_dev_pixelpipe_iop_t *piece = (dt_dev_pixelpipe_iop_t *)nodes->data;
      if(piece == self_piece) break;
      if(piece->enabled && piece->module && piece->module->op[0]) prev_op = piece->module->op;
    }
  }
  if(!IS_NULL_PTR(prev_op) && prev_op[0]) g_snprintf(filter, filter_size, "pre:%s", prev_op);
}
 
static gboolean _background_layer_job_done_idle(gpointer user_data)
{
  dt_drawlayer_io_background_job_result_t *result = (dt_drawlayer_io_background_job_result_t *)user_data;
  if(IS_NULL_PTR(result)) return G_SOURCE_REMOVE;
 
  dt_control_log("%s", result->message[0] ? result->message : _("background layer job finished"));
 
  dt_develop_t *dev = dt_dev_get_global();
 
  gboolean cleared_initiator = FALSE;
  if(dev && dev->image_storage.id == result->imgid)
  {
    for(GList *modules = dev->iop; modules; modules = g_list_next(modules))
    {
      dt_iop_module_t *module = (dt_iop_module_t *)modules->data;
      if(!module || g_strcmp0(module->op, "drawlayer")) continue;
 
      dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(module);
      dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)module->params;
      if(g && params && !g_strcmp0(params->layer_name, result->initiator_layer_name)
         && params->layer_order == result->initiator_layer_order)
      {
        g->session.background_job_running = FALSE;
        if(g->controls.create_background) gtk_widget_set_sensitive(g->controls.create_background, TRUE);
        cleared_initiator = TRUE;
      }
 
      if(result->success && params)
      {
        params->sidecar_timestamp = result->sidecar_timestamp;
        _refresh_layer_widgets(module);
      }
    }
  }
 
  if(!cleared_initiator && dev)
  {
    for(GList *modules = dev->iop; modules; modules = g_list_next(modules))
    {
      dt_iop_module_t *module = (dt_iop_module_t *)modules->data;
      if(!module || g_strcmp0(module->op, "drawlayer")) continue;
      dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(module);
      if(IS_NULL_PTR(g) || !g->session.background_job_running) continue;
      g->session.background_job_running = FALSE;
      if(g->controls.create_background) gtk_widget_set_sensitive(g->controls.create_background, TRUE);
    }
  }
 
  dt_free(result);
  return G_SOURCE_REMOVE;
}
 
static gboolean _create_background_layer_from_input(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return FALSE;
  if(g->session.background_job_running) return FALSE;
  if(!_layer_name_non_empty(params->layer_name)) return FALSE;
 
  if(!_commit_dabs(self, FALSE)) return FALSE;
  if(!_ensure_layer_cache(self)) return FALSE;
  if(!_flush_layer_cache(self)) return FALSE;
 
  dt_dev_pixelpipe_iop_t *piece = dt_dev_distort_get_iop_pipe(self->dev->pipe, self);
  int layer_width = 0;
  int layer_height = 0;
  if(!_resolve_layer_geometry(self, self->dev->pipe, piece, &layer_width, &layer_height, NULL, NULL)) return FALSE;
 
  char sidecar_path[DT_PATH_MAX] = { 0 };
  if(!dt_drawlayer_io_sidecar_path(self->dev->image_storage.id, sidecar_path, sizeof(sidecar_path))) return FALSE;
 
  drawlayer_dir_info_t current_info = { 0 };
  dt_drawlayer_io_layer_info_t io_info = { 0 };
  if(!dt_drawlayer_io_find_layer(sidecar_path, params->layer_name, params->layer_order, &io_info)) return FALSE;
  current_info.found = io_info.found;
  current_info.index = io_info.index;
  current_info.count = io_info.count;
  current_info.width = io_info.width;
  current_info.height = io_info.height;
  g_strlcpy(current_info.name, io_info.name, sizeof(current_info.name));
  g_strlcpy(current_info.work_profile, io_info.work_profile, sizeof(current_info.work_profile));
 
  dt_drawlayer_io_background_job_params_t *job_params = g_new0(dt_drawlayer_io_background_job_params_t, 1);
  job_params->imgid = self->dev->image_storage.id;
  job_params->layer_width = layer_width;
  job_params->layer_height = layer_height;
  job_params->dst_x = 0;
  job_params->dst_y = 0;
  job_params->insert_after_order = current_info.index;
  g_strlcpy(job_params->sidecar_path, sidecar_path, sizeof(job_params->sidecar_path));
  g_strlcpy(job_params->work_profile, params->work_profile, sizeof(job_params->work_profile));
  g_snprintf(job_params->requested_bg_name, sizeof(job_params->requested_bg_name), "%s-bg", params->layer_name);
  g_strlcpy(job_params->initiator_layer_name, params->layer_name, sizeof(job_params->initiator_layer_name));
  job_params->initiator_layer_order = params->layer_order;
  job_params->done_idle = _background_layer_job_done_idle;
  _build_pre_module_filter_string(self, job_params->filter, sizeof(job_params->filter));
 
  dt_job_t *job = dt_control_job_create(dt_drawlayer_io_background_layer_job_run,
                                        "drawlayer create background layer");
  if(IS_NULL_PTR(job))
  {
    dt_free(job_params);
    return FALSE;
  }
 
  dt_control_job_set_params(job, job_params, g_free);
  dt_control_job_add_progress(job, _("creating background layer"), TRUE);
  g->session.background_job_running = TRUE;
  if(g->controls.create_background) gtk_widget_set_sensitive(g->controls.create_background, FALSE);
  if(dt_control_add_job(dt_control_get_global(), DT_JOB_QUEUE_USER_BG, job) != 0)
  {
    g->session.background_job_running = FALSE;
    if(g->controls.create_background) gtk_widget_set_sensitive(g->controls.create_background, TRUE);
    return FALSE;
  }
  return TRUE;
}
 
static void _widget_changed(GtkWidget *widget, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g) || (dt_gui_get_global() && dt_gui_widgets_suppressed())) return;
 
  _sync_params_from_gui(self, FALSE);
 
  if(widget == g->controls.brush_mode || widget == g->controls.brush_shape) _sync_mode_sensitive_widgets(self);
 
  if(widget == g->controls.size || widget == g->controls.softness || widget == g->controls.brush_shape)
    _update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, TRUE);
 
  if(widget == g->controls.hdr_exposure)
  {
    float display_rgb[3] = { 0.0f };
    if(dt_drawlayer_widgets_get_display_color(g->ui.widgets, display_rgb))
      _sync_cached_brush_colors(self, display_rgb);
  }
 
  if(widget == g->controls.brush_shape || widget == g->controls.opacity || widget == g->controls.softness || widget == g->controls.sprinkles
     || widget == g->controls.sprinkle_size || widget == g->controls.sprinkle_coarseness)
    _sync_brush_profile_preview_widget(self);
}
 
static gboolean _apply_selected_layer_attachment(dt_iop_module_t *self, dt_iop_drawlayer_gui_data_t *g,
                                                 dt_iop_drawlayer_params_t *params, const char *layer_name,
                                                 const int layer_order)
{
  if(IS_NULL_PTR(self) || IS_NULL_PTR(g) || IS_NULL_PTR(params) || layer_order < 0 || !_layer_name_non_empty(layer_name)) return FALSE;
 
  char previous_name[DRAWLAYER_NAME_SIZE] = { 0 };
  g_strlcpy(previous_name, params->layer_name, sizeof(previous_name));
  const int previous_order = params->layer_order;
 
  g_strlcpy(params->layer_name, layer_name, sizeof(params->layer_name));
  params->layer_order = layer_order;
  if(!_update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, TRUE).ok)
  {
    g_strlcpy(params->layer_name, previous_name, sizeof(params->layer_name));
    params->layer_order = previous_order;
    gui_update(self);
    return FALSE;
  }
 
  g->session.missing_layer_error[0] = '\0';
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  if(self->dev)
  {
    dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
    dt_dev_pixelpipe_update_history_all(self->dev);
  }
  _refresh_layer_widgets(self);
  return TRUE;
}
 
static void _layer_selected(GtkWidget *widget, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(IS_NULL_PTR(g) || (dt_gui_get_global() && dt_gui_widgets_suppressed())) return;
 
  const int active = dt_bauhaus_combobox_get(widget);
  if(active < 0) return;
 
  const char *text = dt_bauhaus_combobox_get_text(g->controls.layer_select);
  if(IS_NULL_PTR(text)) return;
 
  if(!_layer_name_non_empty(params->layer_name))
  {
    _sync_layer_controls(self);
    return;
  }
  _apply_selected_layer_attachment(self, g, params, text, active);
}
 
static void _attach_selected_layer_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return;
  if(_layer_name_non_empty(params->layer_name)) return;
 
  const int active = dt_bauhaus_combobox_get(g->controls.layer_select);
  if(active < 0) return;
 
  const char *text = dt_bauhaus_combobox_get_text(g->controls.layer_select);
  if(!_layer_name_non_empty(text)) return;
  _apply_selected_layer_attachment(self, g, params, text, active);
}
 
static void _rename_layer_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return;
  if(!_layer_name_non_empty(params->layer_name)) return;
 
  char requested_name[DRAWLAYER_NAME_SIZE] = { 0 };
  if(!_prompt_layer_name_dialog(_("Rename drawing layer"),
                                _("Enter the new name for the current drawing layer."),
                                params->layer_name, requested_name, sizeof(requested_name)))
    return;
 
  if(!_rename_current_layer_from_gui(self, requested_name))
    dt_control_log(_("failed to rename drawing layer"));
}
 
static void _delete_layer_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(IS_NULL_PTR(self->dev)) return;
  if(!_commit_dabs(self, FALSE)) return;
  if(!_confirm_delete_layer(self, FALSE)) return;
 
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  if(self->dev) dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  _refresh_layer_widgets(self);
  gui_update(self);
}
 
static gboolean _fill_current_layer(dt_iop_module_t *self, const float value)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return FALSE;
 
  if(!_commit_dabs(self, FALSE)) return FALSE;
  if(!_update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, FALSE).ok) return FALSE;
  if(IS_NULL_PTR(g->process.base_patch.pixels)) return FALSE;
 
  const size_t count = (size_t)g->process.base_patch.width * g->process.base_patch.height;
  float *const pixels = g->process.base_patch.pixels;
  const float gray = _clamp01(value);
  dt_drawlayer_cache_patch_wrlock(&g->process.base_patch);
  __OMP_PARALLEL_FOR__( if(count > 4096))
  for(size_t k = 0; k < count; k++)
  {
    float *pixel = pixels + 4 * k;
    pixel[0] = gray;
    pixel[1] = gray;
    pixel[2] = gray;
    pixel[3] = 1.0f;
  }
  dt_drawlayer_cache_patch_wrunlock(&g->process.base_patch);
 
  g->process.cache_dirty = TRUE;
  g->process.cache_dirty_rect.valid = TRUE;
  g->process.cache_dirty_rect.nw[0] = 0;
  g->process.cache_dirty_rect.nw[1] = 0;
  g->process.cache_dirty_rect.se[0] = g->process.base_patch.width;
  g->process.cache_dirty_rect.se[1] = g->process.base_patch.height;
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  _reset_stroke_session(g);
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  return TRUE;
}
 
static gboolean _clear_current_layer(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || IS_NULL_PTR(params)) return FALSE;
 
  if(!_commit_dabs(self, FALSE)) return FALSE;
  if(!_update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_SYNC_TEMP_BUFFERS, FALSE).ok) return FALSE;
  if(IS_NULL_PTR(g->process.base_patch.pixels)) return FALSE;
 
  dt_drawlayer_cache_patch_wrlock(&g->process.base_patch);
  dt_drawlayer_cache_clear_transparent_float(g->process.base_patch.pixels,
                                             (size_t)g->process.base_patch.width * g->process.base_patch.height);
  dt_drawlayer_cache_patch_wrunlock(&g->process.base_patch);
 
  g->process.cache_dirty = TRUE;
  g->process.cache_dirty_rect.valid = TRUE;
  g->process.cache_dirty_rect.nw[0] = 0;
  g->process.cache_dirty_rect.nw[1] = 0;
  g->process.cache_dirty_rect.se[0] = g->process.base_patch.width;
  g->process.cache_dirty_rect.se[1] = g->process.base_patch.height;
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  _reset_stroke_session(g);
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  return TRUE;
}
 
static void _fill_white_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(!_fill_current_layer(self, 1.0f)) dt_control_log(_("failed to fill drawing layer"));
}
 
static void _fill_black_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(!_fill_current_layer(self, 0.0f)) dt_control_log(_("failed to fill drawing layer"));
}
 
static void _fill_transparent_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(!_clear_current_layer(self)) dt_control_log(_("failed to clear drawing layer"));
}
 
static void _save_layer_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g)) return;
 
  if(!g->process.cache_valid || IS_NULL_PTR(g->process.base_patch.pixels))
  {
    _show_drawlayer_modal_message(GTK_MESSAGE_ERROR,
                                  _("No drawing layer is loaded in memory."),
                                  _("The sidecar save was aborted."));
    return;
  }
  if(!_layer_name_non_empty(g->process.cache_layer_name))
  {
    _show_drawlayer_modal_message(GTK_MESSAGE_ERROR,
                                  _("Layer name is empty."),
                                  _("The sidecar save was aborted."));
    _refresh_layer_widgets(self);
    return;
  }
 
  GtkWidget *dialog = gtk_message_dialog_new(
      GTK_WINDOW(dt_gui_main_window()), GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_MODAL,
      GTK_MESSAGE_QUESTION, GTK_BUTTONS_NONE, "%s", _("Save the drawing sidecar now?"));
  gtk_message_dialog_format_secondary_text(
      GTK_MESSAGE_DIALOG(dialog), "%s",
      _("This writes the current in-memory drawing layer to the sidecar TIFF immediately."));
  gtk_dialog_add_button(GTK_DIALOG(dialog), _("Cancel"), GTK_RESPONSE_CANCEL);
  gtk_dialog_add_button(GTK_DIALOG(dialog), _("Save"), GTK_RESPONSE_ACCEPT);
 
  const int response = gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
  if(response != GTK_RESPONSE_ACCEPT)
  {
    return;
  }
 
  _drawlayer_wait_for_rasterization_modal(g, _("Saving layer"),
                                          _("Waiting for the layer rasterization to finish..."));
 
  /* Saving the sidecar is explicit persistence, not a history edit.
   * We still finalize any pending stroke first so the flush sees the latest
   * authoritative cache state, then write that cache to the TIFF immediately. */
  if(!_commit_dabs(self, FALSE))
  {
    _show_drawlayer_modal_message(GTK_MESSAGE_ERROR,
                                  _("Failed to finalize the drawing stroke."),
                                  _("The sidecar was not saved."));
    return;
  }
 
  _rekey_shared_base_patch(&g->process.base_patch, self->dev->image_storage.id,
                           (const dt_iop_drawlayer_params_t *)self->params);
 
  if(!_flush_layer_cache(self))
  {
    _show_drawlayer_modal_message(GTK_MESSAGE_ERROR,
                                  _("Failed to write the drawing layer sidecar."),
                                  _("The sidecar TIFF could not be updated."));
    return;
  }
 
  _release_all_base_patch_extra_refs(g);
  _refresh_layer_widgets(self);
 
  _show_drawlayer_modal_message(GTK_MESSAGE_INFO,
                                _("Drawing sidecar saved."),
                                _("The current in-memory layer has been written to the sidecar TIFF."));
}
 
static void _create_layer_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(IS_NULL_PTR(self)) return;
 
  char requested_name[DRAWLAYER_NAME_SIZE] = { 0 };
  if(!_prompt_layer_name_dialog(_("Create drawing layer"),
                                _("Enter the name of the new drawing layer."),
                                "", requested_name, sizeof(requested_name)))
    return;
 
  if(!_create_new_layer(self, requested_name))
    dt_control_log(_("failed to create drawing layer"));
}
 
static void _create_background_clicked(GtkButton *button, gpointer user_data)
{
  (void)button;
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  if(!_create_background_layer_from_input(self)) dt_control_log(_("failed to create background layer from input"));
}
 
static void _preview_bg_toggled(GtkToggleButton *button, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_iop_drawlayer_params_t *params = self ? (dt_iop_drawlayer_params_t *)self->params : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev) || IS_NULL_PTR(g) || (dt_gui_get_global() && dt_gui_widgets_suppressed()) || !gtk_toggle_button_get_active(button))
    return;
 
  if(GTK_WIDGET(button) == g->controls.preview_bg_white)
    g->session.preview_bg_mode = DRAWLAYER_PREVIEW_BG_WHITE;
  else if(GTK_WIDGET(button) == g->controls.preview_bg_grey)
    g->session.preview_bg_mode = DRAWLAYER_PREVIEW_BG_GREY;
  else if(GTK_WIDGET(button) == g->controls.preview_bg_black)
    g->session.preview_bg_mode = DRAWLAYER_PREVIEW_BG_BLACK;
  else
    g->session.preview_bg_mode = DRAWLAYER_PREVIEW_BG_IMAGE;
 
  _sync_preview_bg_buttons(self);
  if(params) _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  dt_dev_pixelpipe_update_history_all(self->dev);
}
 
static gboolean _build_raw_input_event(dt_iop_module_t *self, const double wx, const double wy, const double pressure,
                                       const dt_drawlayer_paint_stroke_pos_t stroke_pos,
                                       dt_drawlayer_paint_raw_input_t *input)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(input)) return FALSE;
 
  dt_control_pointer_input_t pointer_input = { 0 };
  dt_control_get_pointer_input(&pointer_input);
  const float input_wx = isfinite(pointer_input.x) ? (float)pointer_input.x : (float)wx;
  const float input_wy = isfinite(pointer_input.y) ? (float)pointer_input.y : (float)wy;
  const float pressure_norm = pointer_input.has_pressure ? _clamp01(pointer_input.pressure) : _clamp01(pressure);
  *input = (dt_drawlayer_paint_raw_input_t){
    .wx = input_wx,
    .wy = input_wy,
    .pressure = pressure_norm,
    .tilt = (float)_clamp01(pointer_input.tilt),
    .acceleration = (float)_clamp01(pointer_input.acceleration),
    .event_ts = g_get_monotonic_time(),
    .stroke_batch = g->stroke.current_stroke_batch,
    .event_index = ++g->stroke.stroke_event_index,
    .stroke_pos = stroke_pos,
  };
  _fill_input_layer_coords(self, input);
  _fill_input_brush_settings(self, input);
  return TRUE;
}
 
void dt_drawlayer_begin_gui_stroke_capture(dt_iop_module_t *self, const dt_drawlayer_paint_raw_input_t *first_input)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(self) || IS_NULL_PTR(g)) return;
 
  uint32_t stroke_batch = g->stroke.current_stroke_batch + 1u;
  if(stroke_batch == 0u) stroke_batch++;
  const uint32_t event_index = first_input ? first_input->event_index : 0u;
  if(!IS_NULL_PTR(first_input) && first_input->stroke_batch != 0u) stroke_batch = first_input->stroke_batch;
 
  dt_iop_gui_enter_critical_section(self);
  g->session.pointer_valid = TRUE;
  g->stroke.current_stroke_batch = stroke_batch;
  if(!dt_drawlayer_worker_active(g->stroke.worker))
    dt_drawlayer_worker_reset_backend_path(g->stroke.worker);
  g->stroke.finish_commit_pending = FALSE;
  g->stroke.stroke_sample_count = 0;
  g->stroke.stroke_event_index = event_index;
  g->stroke.last_dab_valid = FALSE;
  dt_drawlayer_worker_reset_live_publish(g->stroke.worker);
  dt_iop_gui_leave_critical_section(self);
}
 
void dt_drawlayer_end_gui_stroke_capture(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g)) return;
}
 
static dt_drawlayer_runtime_result_t _update_gui_runtime_manager(dt_iop_module_t *self,
                                                                 dt_iop_drawlayer_gui_data_t *g,
                                                                 const dt_drawlayer_runtime_event_t event,
                                                                 const gboolean flush_pending)
{
  dt_drawlayer_runtime_result_t result = {
    .ok = TRUE,
    .raw_input_ok = TRUE,
  };
  if(IS_NULL_PTR(self) || IS_NULL_PTR(g)) return result;
 
  const drawlayer_runtime_host_context_t runtime_host = {
    .runtime = {
      .self = self,
      .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
      .gui = g,
      .manager = &g->manager,
      .process_state = &g->process,
    },
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = (void *)&runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  return dt_drawlayer_runtime_manager_update(
      &g->manager,
      &(dt_drawlayer_runtime_update_request_t){
        .event = event,
        .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
        .flush_pending = flush_pending,
      },
      &runtime_manager);
}
 
void dt_drawlayer_show_runtime_feedback(const dt_iop_drawlayer_gui_data_t *g,
                                        const dt_drawlayer_runtime_feedback_t feedback)
{
  if(IS_NULL_PTR(g)) return;
 
  switch(feedback)
  {
    case DT_DRAWLAYER_RUNTIME_FEEDBACK_FOCUS_LOSS_WAIT:
      _drawlayer_wait_for_rasterization_modal(g, _("Finishing drawing"),
                                              _("Waiting for the drawing rasterization to finish..."));
      break;
 
    case DT_DRAWLAYER_RUNTIME_FEEDBACK_SAVE_WAIT:
      _drawlayer_wait_for_rasterization_modal(g, _("Saving layer"),
                                              _("Waiting for the layer rasterization to finish..."));
      break;
 
    case DT_DRAWLAYER_RUNTIME_FEEDBACK_NONE:
    default:
      break;
  }
}
 
const char *name()
{
  return C_("modulename", "drawing");
}
 
const char **description(struct dt_iop_module_t *self)
{
  return dt_iop_set_description(self, _("paint premultiplied RGB layers in a TIFF sidecar"), _("creative"),
                                _("linear, RGB, scene-referred"), _("geometric, RGB"),
                                _("linear, RGB, scene-referred"));
}
 
#ifdef HAVE_OPENCL
void init_global(dt_iop_module_so_t *module)
{
  const int program = 3; // blendop.cl, from programs.conf
  dt_iop_drawlayer_global_data_t *gd = calloc(1, sizeof(*gd));
  if(IS_NULL_PTR(gd)) return;
  module->data = gd;
  gd->kernel_premult_over = -1;
 
  /* Reuse the existing blendop OpenCL program and add one drawlayer-specific
   * kernel to handle premultiplied "over" directly. This avoids the costly
   * de-premultiply + mask split that the stock blend kernels would require. */
  gd->kernel_premult_over = dt_opencl_create_kernel(program, "blendop_premult_over");
}
 
void cleanup_global(dt_iop_module_so_t *module)
{
  dt_iop_drawlayer_global_data_t *gd = (dt_iop_drawlayer_global_data_t *)module->data;
  if(IS_NULL_PTR(gd)) return;
  dt_opencl_free_kernel(gd->kernel_premult_over);
  dt_free(gd);
  module->data = NULL;
}
#endif
 
int default_group()
{
  return IOP_GROUP_EFFECTS;
}
 
int flags()
{
  return IOP_FLAGS_SUPPORTS_BLENDING;
}
 
int default_colorspace(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece)
{
  return IOP_CS_RGB;
}
 
void init(dt_iop_module_t *module)
{
  module->params = calloc(1, sizeof(dt_iop_drawlayer_params_t));
  module->default_params = calloc(1, sizeof(dt_iop_drawlayer_params_t));
  module->params_size = sizeof(dt_iop_drawlayer_params_t);
 
  if(module->params) ((dt_iop_drawlayer_params_t *)module->params)->layer_order = -1;
  if(module->default_params) ((dt_iop_drawlayer_params_t *)module->default_params)->layer_order = -1;
}
 
void init_pipe(struct dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  /* The aligned family, like every other module: the DEFAULT cleanup_pipe frees
   * piece->data with dt_free_align(), so a module that allocates any other way only stays
   * correct for as long as it also overrides cleanup_pipe. That is a standing trap on
   * Windows -- _aligned_malloc against g_free -- and invisible on Linux, where both end at
   * free(). */
  piece->data = dt_calloc_align(sizeof(dt_iop_drawlayer_data_t));
  if(IS_NULL_PTR(piece->data)) return;
  piece->data_size = sizeof(dt_iop_drawlayer_params_t);
  dt_iop_drawlayer_data_t *data = (dt_iop_drawlayer_data_t *)piece->data;
  data->params.layer_order = -1;
  dt_drawlayer_process_state_init(&data->process);
  dt_drawlayer_runtime_manager_init(&data->headless_manager);
  dt_drawlayer_runtime_manager_bind_piece(&data->headless_manager, &data->process, NULL, NULL, FALSE,
                                          &data->runtime_manager, &data->runtime_process,
                                          &data->runtime_display_pipe);
}
 
void cleanup_pipe(struct dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  (void)self;
  (void)pipe;
  if(IS_NULL_PTR(piece) || IS_NULL_PTR(piece->data)) return;
  dt_iop_drawlayer_data_t *data = (dt_iop_drawlayer_data_t *)piece->data;
  dt_drawlayer_process_state_cleanup(&data->process);
  dt_drawlayer_runtime_manager_cleanup(&data->headless_manager);
  dt_free_align(piece->data);
  piece->data_size = 0;
}
 
void commit_params(dt_iop_module_t *self, dt_iop_params_t *params, dt_dev_pixelpipe_t *pipe,
                   dt_dev_pixelpipe_iop_t *piece)
{
  dt_iop_drawlayer_data_t *data = (dt_iop_drawlayer_data_t *)piece->data;
  const gboolean display_pipe = self && self->dev && dt_iop_gui_data(self) && pipe
                                && (pipe == self->dev->pipe || pipe == self->dev->preview_pipe);
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  dt_drawlayer_runtime_manager_bind_piece(&data->headless_manager, &data->process, g ? &g->manager : NULL,
                                          g ? &g->process : NULL, display_pipe, &data->runtime_manager,
                                          &data->runtime_process, &data->runtime_display_pipe);
  memcpy(&data->params, params, sizeof(dt_iop_drawlayer_params_t));
  _sanitize_params(self, &data->params);
 
  /* Every pipe now warms the same authoritative base-patch snapshot through
   * the pixelpipe cache during `commit_params()`. GUI pipes still keep their
   * own transformed ROI cache on top, but they attach to the same shared base
   * line as headless pipes instead of carrying a private sidecar mirror. */
  _refresh_piece_base_cache(self, data, &data->params, pipe, piece);
}
 
void gui_reset(dt_iop_module_t *self)
{
  if(IS_NULL_PTR(self) || IS_NULL_PTR(self->dev)) return;
  if(!_commit_dabs(self, FALSE)) return;
  if(!_confirm_delete_layer(self, FALSE)) return;
 
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  params->layer_name[0] = '\0';
  params->layer_order = -1;
  params->sidecar_timestamp = 0;
  memset(params->work_profile, 0, sizeof(params->work_profile));
  _touch_stroke_commit_hash(params, 0, FALSE, 0.0f, 0.0f, 0u);
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(!IS_NULL_PTR(g))
  {
    g->session.missing_layer_error[0] = '\0';
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    dt_drawlayer_runtime_manager_update(
        &g->manager,
        &(dt_drawlayer_runtime_update_request_t){
          .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RESYNC,
          .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
        },
        &runtime_manager);
  }
 
  _sync_mode_sensitive_widgets(self);
  _refresh_layer_widgets(self);
}
 
gboolean module_will_remove(dt_iop_module_t *self)
{
  if(IS_NULL_PTR(self->dev)) return TRUE;
  if(!_commit_dabs(self, FALSE)) return FALSE;
  _flush_layer_cache(self);
  return _confirm_delete_layer(self, TRUE);
}
 
void gui_init(dt_iop_module_t *self)
{
  IOP_GUI_ALLOC(drawlayer);
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  _ensure_gui_conf_defaults();
  g->ui.widgets = dt_drawlayer_widgets_init();
  dt_drawlayer_runtime_manager_init(&g->manager);
  dt_drawlayer_process_state_init(&g->process);
  _load_color_history(g);
  _sanitize_params(self, params);
 
  dt_drawlayer_worker_init(self, &g->stroke.worker, &g->manager.painting_active,
                           &g->stroke.finish_commit_pending, &g->stroke.stroke_sample_count,
                           &g->stroke.current_stroke_batch);
  g->session.background_job_running = FALSE;
  g->session.last_view_x = 0.0f;
  g->session.last_view_y = 0.0f;
  g->session.last_view_scale = 1.0f;
  if(self->dev)
  {
    g->session.last_view_x = dt_dev_viewport_center_x(self->dev);
    g->session.last_view_y = dt_dev_viewport_center_y(self->dev);
    g->session.last_view_scale = dt_dev_viewport_scaling(self->dev);
  }
 
  self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  if(self->gui->reset_button) gtk_widget_hide(self->gui->reset_button);
 
  GtkWidget *history_box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.save_layer = gtk_button_new_with_label(_("save sidecar"));
  gtk_box_pack_start(GTK_BOX(history_box), g->controls.save_layer, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), history_box, FALSE, FALSE, 0);
 
  GtkWidget *notebook = gtk_notebook_new();
  g->controls.notebook = notebook;
  gtk_widget_set_hexpand(notebook, TRUE);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), notebook, FALSE, FALSE, 0);
  // image_colorpicker lives on the "Brush" tab; reset it if still active once the
  // user switches away from that tab.
  dt_ui_notebook_set_picker_owner(GTK_NOTEBOOK(notebook), self);
 
  GtkWidget *brush_tab = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  GtkWidget *layer_tab = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  GtkWidget *input_tab = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  g->controls.brush_tab = brush_tab;
  g->controls.layer_tab = layer_tab;
  g->controls.input_tab = input_tab;
 
  gtk_notebook_append_page(GTK_NOTEBOOK(notebook), brush_tab, gtk_label_new(_("Brush")));
  gtk_notebook_append_page(GTK_NOTEBOOK(notebook), layer_tab, gtk_label_new(_("Layer")));
  gtk_notebook_append_page(GTK_NOTEBOOK(notebook), input_tab, gtk_label_new(_("Input")));
  gtk_container_child_set(GTK_CONTAINER(notebook), brush_tab, "tab-expand", TRUE, "tab-fill", TRUE, NULL);
  gtk_container_child_set(GTK_CONTAINER(notebook), layer_tab, "tab-expand", TRUE, "tab-fill", TRUE, NULL);
  gtk_container_child_set(GTK_CONTAINER(notebook), input_tab, "tab-expand", TRUE, "tab-fill", TRUE, NULL);
 
  GtkWidget *preview_title = gtk_label_new(_("Background"));
  g->controls.preview_title = preview_title;
  gtk_widget_set_halign(preview_title, GTK_ALIGN_START);
  GtkWidget *preview_box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.preview_box = preview_box;
  GSList *preview_group = NULL;
  g->controls.preview_bg_image = gtk_radio_button_new_with_label(preview_group, _("image"));
  preview_group = gtk_radio_button_get_group(GTK_RADIO_BUTTON(g->controls.preview_bg_image));
  g->controls.preview_bg_white = gtk_radio_button_new_with_label(preview_group, _("white"));
  preview_group = gtk_radio_button_get_group(GTK_RADIO_BUTTON(g->controls.preview_bg_white));
  g->controls.preview_bg_grey = gtk_radio_button_new_with_label(preview_group, _("grey"));
  preview_group = gtk_radio_button_get_group(GTK_RADIO_BUTTON(g->controls.preview_bg_grey));
  g->controls.preview_bg_black = gtk_radio_button_new_with_label(preview_group, _("black"));
  gtk_box_pack_start(GTK_BOX(preview_box), g->controls.preview_bg_image, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(preview_box), g->controls.preview_bg_white, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(preview_box), g->controls.preview_bg_grey, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(preview_box), g->controls.preview_bg_black, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_tab), preview_title, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_tab), preview_box, FALSE, FALSE, 0);
 
  g->controls.brush_mode = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self));
  dt_bauhaus_combobox_add(g->controls.brush_mode, _("paint"));
  dt_bauhaus_combobox_add(g->controls.brush_mode, _("erase"));
  dt_bauhaus_combobox_add(g->controls.brush_mode, _("blur"));
  dt_bauhaus_combobox_add(g->controls.brush_mode, _("smudge"));
  dt_bauhaus_widget_set_label(g->controls.brush_mode, _("Paint mode"));
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.brush_mode, TRUE, TRUE, 0);
 
  GtkWidget *color_title = gtk_label_new(_("Color"));
  gtk_label_set_xalign(GTK_LABEL(color_title), 0.0f);
  dt_gui_add_class(color_title, "dt_section_label");
  gtk_box_pack_start(GTK_BOX(brush_tab), color_title, TRUE, TRUE, 0);
  g->controls.color = gtk_drawing_area_new();
  gtk_widget_set_size_request(g->controls.color, -1, DT_DRAWLAYER_COLOR_PICKER_HEIGHT);
  gtk_widget_add_events(g->controls.color, GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK);
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.color, TRUE, TRUE, 0);
  g->controls.color_row = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.color_swatch = gtk_drawing_area_new();
  gtk_widget_set_size_request(g->controls.color_swatch, -1, DT_PIXEL_APPLY_DPI(DT_DRAWLAYER_COLOR_HISTORY_HEIGHT));
  gtk_widget_add_events(g->controls.color_swatch, GDK_BUTTON_PRESS_MASK);
  gtk_box_pack_start(GTK_BOX(g->controls.color_row), g->controls.color_swatch, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.color_row, TRUE, TRUE, 0);
  GtkWidget *picker_controls = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.image_colorpicker = dt_color_picker_new_with_cst(self, DT_COLOR_PICKER_POINT_AREA, NULL, IOP_CS_NONE);
  g->controls.image_colorpicker_source = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self));
  dt_bauhaus_combobox_add(g->controls.image_colorpicker_source, _("input"));
  dt_bauhaus_combobox_add(g->controls.image_colorpicker_source, _("output"));
  dt_bauhaus_widget_set_label(g->controls.image_colorpicker_source, _("Pick from"));
  gtk_box_pack_start(GTK_BOX(picker_controls), g->controls.image_colorpicker, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(picker_controls), g->controls.image_colorpicker_source, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(brush_tab), picker_controls, TRUE, TRUE, 0);
 
  g->controls.hdr_exposure
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 4.0f, 0.1f, 0.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.hdr_exposure, _("HDR exposure"));
  dt_bauhaus_slider_set_format(g->controls.hdr_exposure, _(" EV"));
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.hdr_exposure, TRUE, TRUE, 0);
 
  GtkWidget *geometry_title = gtk_label_new(_("Geometry"));
  gtk_label_set_xalign(GTK_LABEL(geometry_title), 0.0f);
  dt_gui_add_class(geometry_title, "dt_section_label");
  gtk_box_pack_start(GTK_BOX(brush_tab), geometry_title, TRUE, TRUE, 0);
  GtkWidget *brush_shape_title = gtk_label_new(_("Fall-off"));
  gtk_label_set_xalign(GTK_LABEL(brush_shape_title), 0.0f);
  gtk_box_pack_start(GTK_BOX(brush_tab), brush_shape_title, TRUE, TRUE, 0);
  g->controls.brush_shape = gtk_drawing_area_new();
  gtk_widget_set_size_request(g->controls.brush_shape, -1, DT_PIXEL_APPLY_DPI(72));
  gtk_widget_add_events(g->controls.brush_shape, GDK_BUTTON_PRESS_MASK);
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.brush_shape, TRUE, TRUE, 0);
 
  g->controls.size
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 1.0f, 2048.0f, 1.0f, 64.0f, 0);
  dt_bauhaus_widget_set_label(g->controls.size, _("Size"));
  dt_bauhaus_slider_set_format(g->controls.size, _(" px"));
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.size, TRUE, TRUE, 0);
  g->controls.distance
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 0.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.distance, _("Sampling distance"));
  dt_bauhaus_slider_set_format(g->controls.distance, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.distance, TRUE, TRUE, 0);
  g->controls.smoothing
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 0.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.smoothing, _("Smoothing"));
  dt_bauhaus_slider_set_format(g->controls.smoothing, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.smoothing, TRUE, TRUE, 0);
  g->controls.softness
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 1.0f, 0.01f, 0.5f, 2);
  dt_bauhaus_widget_set_label(g->controls.softness, _("Hardness"));
  dt_bauhaus_slider_set_factor(g->controls.softness, 100.0f);
  dt_bauhaus_slider_set_format(g->controls.softness, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.softness, TRUE, TRUE, 0);
 
  GtkWidget *thickness_title = gtk_label_new(_("Thickness"));
  gtk_label_set_xalign(GTK_LABEL(thickness_title), 0.0f);
  dt_gui_add_class(thickness_title, "dt_section_label");
  gtk_box_pack_start(GTK_BOX(brush_tab), thickness_title, TRUE, TRUE, 0);
  g->controls.opacity
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 100.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.opacity, _("Opacity"));
  dt_bauhaus_slider_set_format(g->controls.opacity, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.opacity, TRUE, TRUE, 0);
  g->controls.flow
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 100.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.flow, _("Flow"));
  dt_bauhaus_slider_set_format(g->controls.flow, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.flow, TRUE, TRUE, 0);
 
  GtkWidget *texture_title = gtk_label_new(_("Texture"));
  gtk_label_set_xalign(GTK_LABEL(texture_title), 0.0f);
  dt_gui_add_class(texture_title, "dt_section_label");
  gtk_box_pack_start(GTK_BOX(brush_tab), texture_title, TRUE, TRUE, 0);
  g->controls.sprinkles
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 0.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.sprinkles, _("Sprinkles"));
  dt_bauhaus_slider_set_format(g->controls.sprinkles, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.sprinkles, TRUE, TRUE, 0);
  g->controls.sprinkle_size
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 1.0f, 256.0f, 1.0f, 3.0f, 0);
  dt_bauhaus_widget_set_label(g->controls.sprinkle_size, _("Sprinkle size"));
  dt_bauhaus_slider_set_format(g->controls.sprinkle_size, _(" px"));
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.sprinkle_size, TRUE, TRUE, 0);
  g->controls.sprinkle_coarseness
      = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(self), 0.0f, 100.0f, 1.0f, 50.0f, 2);
  dt_bauhaus_widget_set_label(g->controls.sprinkle_coarseness, _("Coarseness"));
  dt_bauhaus_slider_set_format(g->controls.sprinkle_coarseness, "%");
  gtk_box_pack_start(GTK_BOX(brush_tab), g->controls.sprinkle_coarseness, TRUE, TRUE, 0);
 
  GtkWidget *layer_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  GtkWidget *layer_status = gtk_label_new("");
  g->controls.layer_status = layer_status;
  gtk_widget_set_halign(layer_status, GTK_ALIGN_START);
  gtk_label_set_xalign(GTK_LABEL(layer_status), 0.0f);
  gtk_label_set_line_wrap(GTK_LABEL(layer_status), TRUE);
  GtkWidget *layer_fill_title = gtk_label_new(_("Fill"));
  g->controls.layer_fill_title = layer_fill_title;
  gtk_widget_set_halign(layer_fill_title, GTK_ALIGN_START);
  GtkWidget *layer_action_row = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.layer_action_row = layer_action_row;
  GtkWidget *layer_fill_row = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  g->controls.layer_fill_row = layer_fill_row;
  g->controls.layer_select = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self));
  dt_bauhaus_widget_set_label(g->controls.layer_select, _("Source layer"));
  g->controls.delete_layer = gtk_button_new_with_label(_("delete layer"));
  g->controls.create_layer = gtk_button_new_with_label(_("create new layer"));
  g->controls.rename_layer = gtk_button_new_with_label(_("rename layer"));
  g->controls.attach_layer = gtk_button_new_with_label(_("reuse selected layer"));
  g->controls.create_background = gtk_button_new_with_label(_("create background from input"));
  g->controls.fill_white = gtk_button_new_with_label(_("white"));
  g->controls.fill_black = gtk_button_new_with_label(_("black"));
  g->controls.fill_transparent = gtk_button_new_with_label(_("transparency"));
  gtk_box_pack_start(GTK_BOX(layer_box), layer_status, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_box), g->controls.layer_select, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_action_row), g->controls.create_layer, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_action_row), g->controls.rename_layer, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_action_row), g->controls.attach_layer, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_action_row), g->controls.delete_layer, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_box), layer_action_row, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_box), layer_fill_title, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_fill_row), g->controls.fill_white, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_fill_row), g->controls.fill_black, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_fill_row), g->controls.fill_transparent, TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(layer_box), layer_fill_row, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_box), g->controls.create_background, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(layer_tab), layer_box, FALSE, FALSE, 0);
 
  GtkWidget *mapping_title = gtk_label_new(_("tablet mapping"));
  gtk_widget_set_halign(mapping_title, GTK_ALIGN_START);
  GtkWidget *grid = gtk_grid_new();
  gtk_grid_set_row_spacing(GTK_GRID(grid), DT_GUI_BOX_SPACING);
  gtk_grid_set_column_spacing(GTK_GRID(grid), DT_GUI_BOX_SPACING);
 
  const char *labels[4] = { _("size"), _("opacity"), _("flow"), _("hardness") };
  const char *rows[3] = { _("pressure"), _("tilt"), _("acceleration") };
  GtkWidget **targets[3][4] = {
    { &g->controls.map_pressure_size, &g->controls.map_pressure_opacity, &g->controls.map_pressure_flow, &g->controls.map_pressure_softness },
    { &g->controls.map_tilt_size, &g->controls.map_tilt_opacity, &g->controls.map_tilt_flow, &g->controls.map_tilt_softness },
    { &g->controls.map_accel_size, &g->controls.map_accel_opacity, &g->controls.map_accel_flow, &g->controls.map_accel_softness },
  };
  GtkWidget **profiles[3] = { &g->controls.pressure_profile, &g->controls.tilt_profile, &g->controls.accel_profile };
 
  for(int c = 0; c < 4; c++)
  {
    GtkWidget *label = gtk_label_new(labels[c]);
    gtk_label_set_angle(GTK_LABEL(label), 90.0);
    gtk_grid_attach(GTK_GRID(grid), label, c + 1, 0, 1, 1);
  }
  gtk_grid_attach(GTK_GRID(grid), gtk_label_new(_("profile")), 5, 0, 1, 1);
 
  for(int r = 0; r < 3; r++)
  {
    gtk_grid_attach(GTK_GRID(grid), gtk_label_new(rows[r]), 0, r + 1, 1, 1);
    for(int c = 0; c < 4; c++)
    {
      *targets[r][c] = gtk_check_button_new();
      gtk_grid_attach(GTK_GRID(grid), *targets[r][c], c + 1, r + 1, 1, 1);
    }
    *profiles[r] = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self));
    dt_bauhaus_combobox_add(*profiles[r], _("linear"));
    dt_bauhaus_combobox_add(*profiles[r], _("quadratic"));
    dt_bauhaus_combobox_add(*profiles[r], _("square root"));
    dt_bauhaus_combobox_add(*profiles[r], _("inverse linear"));
    dt_bauhaus_combobox_add(*profiles[r], _("inverse square root"));
    dt_bauhaus_combobox_add(*profiles[r], _("inverse quadratic"));
    gtk_grid_attach(GTK_GRID(grid), *profiles[r], 5, r + 1, 1, 1);
  }
 
  gtk_box_pack_start(GTK_BOX(input_tab), mapping_title, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(input_tab), grid, FALSE, FALSE, 0);
 
  g_signal_connect(g->controls.brush_shape, "draw", G_CALLBACK(_brush_profile_draw), self);
  g_signal_connect(g->controls.brush_shape, "button-press-event", G_CALLBACK(_brush_profile_button_press), self);
  g_signal_connect(G_OBJECT(g->controls.brush_mode), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(g->controls.color, "draw", G_CALLBACK(_color_picker_draw), self);
  g_signal_connect(g->controls.color_swatch, "draw", G_CALLBACK(_color_swatch_draw), self);
  g_signal_connect(g->controls.color_swatch, "button-press-event", G_CALLBACK(_color_swatch_button_press), self);
  g_signal_connect(g->controls.color, "button-press-event", G_CALLBACK(_color_picker_button_press), self);
  g_signal_connect(g->controls.color, "button-release-event", G_CALLBACK(_color_picker_button_release), self);
  g_signal_connect(g->controls.color, "motion-notify-event", G_CALLBACK(_color_picker_motion), self);
  g_signal_connect(G_OBJECT(g->controls.image_colorpicker_source), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.size), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.distance), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.smoothing), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.opacity), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.flow), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.sprinkles), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.sprinkle_size), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.sprinkle_coarseness), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.softness), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.hdr_exposure), "value-changed", G_CALLBACK(_widget_changed), self);
  g_signal_connect(G_OBJECT(g->controls.layer_select), "value-changed", G_CALLBACK(_layer_selected), self);
  g_signal_connect(g->controls.preview_bg_image, "toggled", G_CALLBACK(_preview_bg_toggled), self);
  g_signal_connect(g->controls.preview_bg_white, "toggled", G_CALLBACK(_preview_bg_toggled), self);
  g_signal_connect(g->controls.preview_bg_grey, "toggled", G_CALLBACK(_preview_bg_toggled), self);
  g_signal_connect(g->controls.preview_bg_black, "toggled", G_CALLBACK(_preview_bg_toggled), self);
  g_signal_connect(g->controls.create_layer, "clicked", G_CALLBACK(_create_layer_clicked), self);
  g_signal_connect(g->controls.rename_layer, "clicked", G_CALLBACK(_rename_layer_clicked), self);
  g_signal_connect(g->controls.attach_layer, "clicked", G_CALLBACK(_attach_selected_layer_clicked), self);
  g_signal_connect(g->controls.create_background, "clicked", G_CALLBACK(_create_background_clicked), self);
  g_signal_connect(g->controls.save_layer, "clicked", G_CALLBACK(_save_layer_clicked), self);
  g_signal_connect(g->controls.delete_layer, "clicked", G_CALLBACK(_delete_layer_clicked), self);
  g_signal_connect(g->controls.fill_white, "clicked", G_CALLBACK(_fill_white_clicked), self);
  g_signal_connect(g->controls.fill_black, "clicked", G_CALLBACK(_fill_black_clicked), self);
  g_signal_connect(g->controls.fill_transparent, "clicked", G_CALLBACK(_fill_transparent_clicked), self);
 
  for(int r = 0; r < 3; r++)
  {
    for(int c = 0; c < 4; c++) g_signal_connect(*targets[r][c], "toggled", G_CALLBACK(_widget_changed), self);
    g_signal_connect(G_OBJECT(*profiles[r]), "value-changed", G_CALLBACK(_widget_changed), self);
  }
 
  DT_DEBUG_CONTROL_SIGNAL_CONNECT(dt_control_signal_get_global(), DT_SIGNAL_DEVELOP_UI_PIPE_FINISHED,
                                  G_CALLBACK(_develop_ui_pipe_finished_callback), self);
 
  if(self->dev)
  {
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    dt_drawlayer_runtime_manager_update(
        &g->manager,
        &(dt_drawlayer_runtime_update_request_t){
          .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RESYNC,
          .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
        },
        &runtime_manager);
  }
}
 
void gui_update(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(IS_NULL_PTR(g)) return;
 
  _sanitize_params(self, params);
 
  dt_bauhaus_combobox_set(g->controls.brush_mode, _conf_brush_mode());
  dt_bauhaus_slider_set(g->controls.size, _conf_size());
  dt_bauhaus_slider_set(g->controls.distance, _conf_distance());
  dt_bauhaus_slider_set(g->controls.smoothing, _conf_smoothing());
  dt_bauhaus_slider_set(g->controls.opacity, _conf_opacity());
  dt_bauhaus_slider_set(g->controls.flow, _conf_flow());
  dt_bauhaus_slider_set(g->controls.sprinkles, _conf_sprinkles());
  dt_bauhaus_slider_set(g->controls.sprinkle_size, _conf_sprinkle_size());
  dt_bauhaus_slider_set(g->controls.sprinkle_coarseness, _conf_sprinkle_coarseness());
  dt_bauhaus_slider_set(g->controls.softness, _conf_hardness());
  if(g->controls.image_colorpicker_source) dt_bauhaus_combobox_set(g->controls.image_colorpicker_source, _conf_pick_source());
  dt_bauhaus_slider_set(g->controls.hdr_exposure, _conf_hdr_exposure());
 
  _sync_color_picker_from_conf(self);
  _sync_brush_profile_preview_widget(self);
  if(g->controls.color) gtk_widget_queue_draw(g->controls.color);
 
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_pressure_size))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_pressure_size),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SIZE));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_pressure_opacity))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_pressure_opacity),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_OPACITY));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_pressure_flow))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_pressure_flow),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_FLOW));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_pressure_softness))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_pressure_softness),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SOFTNESS));
 
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_tilt_size))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_tilt_size),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SIZE));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_tilt_opacity))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_tilt_opacity),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_OPACITY));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_tilt_flow))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_tilt_flow),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_FLOW));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_tilt_softness))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_tilt_softness),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SOFTNESS));
 
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_accel_size))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_accel_size),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SIZE));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_accel_opacity))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_accel_opacity),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_OPACITY));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_accel_flow))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_accel_flow),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_FLOW));
  if(GTK_IS_TOGGLE_BUTTON(g->controls.map_accel_softness))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(g->controls.map_accel_softness),
                                 dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SOFTNESS));
 
  if(g->controls.pressure_profile)
    dt_bauhaus_combobox_set(g->controls.pressure_profile, _conf_mapping_profile(DRAWLAYER_CONF_PRESSURE_PROFILE));
  if(g->controls.tilt_profile) dt_bauhaus_combobox_set(g->controls.tilt_profile, _conf_mapping_profile(DRAWLAYER_CONF_TILT_PROFILE));
  if(g->controls.accel_profile)
    dt_bauhaus_combobox_set(g->controls.accel_profile, _conf_mapping_profile(DRAWLAYER_CONF_ACCEL_PROFILE));
 
  _sync_mode_sensitive_widgets(self);
  _sync_preview_bg_buttons(self);
  _populate_layer_list(self);
  _sync_layer_controls(self);
 
  if(self->dev)
  {
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    dt_drawlayer_runtime_manager_update(
        &g->manager,
        &(dt_drawlayer_runtime_update_request_t){
          .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RESYNC,
          .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
        },
        &runtime_manager);
  }
}
 
void change_image(dt_iop_module_t *self)
{
  if(dt_iop_gui_data(self))
  {
    dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
    g->session.missing_layer_error[0] = '\0';
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_CHANGE_IMAGE,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  }
}
 
void gui_focus(dt_iop_module_t *self, gboolean in)
{
  if(!in)
  {
    dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
    dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
    const int pending_samples = g ? (int)g->stroke.stroke_sample_count : 0;
    const gboolean had_pending_edits
        = (g && (g->process.cache_dirty || g->stroke.stroke_sample_count > 0));
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_FOCUS_LOSS,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    dt_control_set_cursor_visible(TRUE);
    if(g) dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
    if(had_pending_edits && params)
      _touch_stroke_commit_hash(params, pending_samples, g->stroke.last_dab_valid, g->stroke.last_dab_x,
                                g->stroke.last_dab_y, 0u);
    if(had_pending_edits && self->dev && !IS_NULL_PTR(params))
    {
      dt_dev_undo_start_record(self->dev);
      dt_pthread_rwlock_wrlock(&self->dev->history_mutex);
      dt_dev_add_history_item_ext(self->dev, self, TRUE, FALSE);
      dt_dev_set_history_hash(self->dev, dt_dev_history_compute_hash(self->dev));
      dt_pthread_rwlock_unlock(&self->dev->history_mutex);
      dt_dev_undo_end_record(self->dev);
      if(self->post_history_commit) self->post_history_commit(self);
      dt_dev_write_history(self->dev, FALSE);
      dt_dev_history_notify_change(self->dev, self->dev->image_storage.id);
    }
  }
  else if(dt_iop_gui_data(self))
  {
    dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_FOCUS_GAIN,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  }
}
 
void quiesce(dt_iop_module_t *self)
{
  /* Darkroom is leaving and is about to tear down the pixelpipe nodes and history. The paint worker
   * runs stroke commits off the GUI thread, and a commit performs a full pipeline history resync
   * (dt_dev_pixelpipe_update_history_all) that reads/commits every pipe piece. If that runs while
   * leave() frees the nodes, it faults on freed piece->data. Stop and join the worker now, while the
   * pipe is still alive, so any in-flight commit completes against valid nodes and no further commit
   * can start during teardown. */
  dt_iop_drawlayer_gui_data_t *g = self ? (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self) : NULL;
  if(IS_NULL_PTR(g)) return;
  dt_drawlayer_worker_stop(self, g->stroke.worker);
}
 
void gui_cleanup(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g)) return;
 
  dt_control_set_cursor_visible(TRUE);
  _update_gui_runtime_manager(self, g, DT_DRAWLAYER_RUNTIME_EVENT_GUI_FOCUS_LOSS, FALSE);
 
  DT_DEBUG_CONTROL_SIGNAL_DISCONNECT(dt_control_signal_get_global(), G_CALLBACK(_develop_ui_pipe_finished_callback), self);
 
  _release_all_base_patch_extra_refs(g);
  dt_drawlayer_process_state_cleanup(&g->process);
  dt_drawlayer_runtime_manager_cleanup(&g->manager);
  memset(&g->session.live_patch, 0, sizeof(g->session.live_patch));
  dt_drawlayer_widgets_cleanup(&g->ui.widgets);
  dt_drawlayer_ui_cursor_clear(&g->ui);
  dt_drawlayer_worker_cleanup(&g->stroke.worker);
  
  IOP_GUI_FREE;
}
 
typedef struct drawlayer_hud_brush_state_t
{
  float pressure;
  float tilt;
  float acceleration;
  float radius;
  float opacity;
  float flow;
  float hardness;
} drawlayer_hud_brush_state_t;
 
static void _compute_hud_brush_state(const dt_control_pointer_input_t *pointer_input,
                                     drawlayer_hud_brush_state_t *state)
{
  if(IS_NULL_PTR(state)) return;
 
  const float pressure_norm
      = _clamp01((pointer_input && pointer_input->has_pressure) ? pointer_input->pressure : 1.0f);
  const float tilt_norm = _clamp01((pointer_input && pointer_input->has_tilt) ? pointer_input->tilt : 0.0f);
  const float accel_norm = _clamp01(pointer_input ? pointer_input->acceleration : 0.0f);
  const drawlayer_mapping_profile_t pressure_profile = _conf_mapping_profile(DRAWLAYER_CONF_PRESSURE_PROFILE);
  const drawlayer_mapping_profile_t tilt_profile = _conf_mapping_profile(DRAWLAYER_CONF_TILT_PROFILE);
  const drawlayer_mapping_profile_t accel_profile = _conf_mapping_profile(DRAWLAYER_CONF_ACCEL_PROFILE);
  const float pressure_coeff = _mapping_profile_value(pressure_profile, pressure_norm);
  const float tilt_coeff = _mapping_profile_value(tilt_profile, tilt_norm);
  const float accel_coeff = _mapping_profile_value(accel_profile, accel_norm);
 
  float radius = _conf_size();
  float opacity = _conf_opacity() / 100.0f;
  float flow = _conf_flow() / 100.0f;
  float hardness = _conf_hardness();
 
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SIZE)) radius *= pressure_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_OPACITY)) opacity *= pressure_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_FLOW)) flow *= pressure_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_PRESSURE_SOFTNESS)) hardness *= pressure_coeff;
 
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SIZE)) radius *= tilt_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_OPACITY)) opacity *= tilt_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_FLOW)) flow *= tilt_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_TILT_SOFTNESS)) hardness *= tilt_coeff;
 
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SIZE)) radius *= accel_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_OPACITY)) opacity *= accel_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_FLOW)) flow *= accel_coeff;
  if(dt_conf_get_bool(DRAWLAYER_CONF_MAP_ACCEL_SOFTNESS)) hardness *= accel_coeff;
 
  state->pressure = pressure_norm;
  state->tilt = tilt_norm;
  state->acceleration = accel_norm;
  state->radius = fmaxf(0.5f, radius);
  state->opacity = _clamp01(opacity);
  state->flow = _clamp01(flow);
  state->hardness = _clamp01(hardness);
}
 
static void _draw_brush_hud(cairo_t *cr, const drawlayer_hud_brush_state_t *state)
{
  if(IS_NULL_PTR(cr) || IS_NULL_PTR(state)) return;
 
  char lines[3][128] = { { 0 } };
  g_snprintf(lines[0], sizeof(lines[0]), _("size %.1f px  hardness %.2f%%"), state->radius * 2.0f,
             state->hardness * 100.0f);
  g_snprintf(lines[1], sizeof(lines[1]), _("opacity %.2f%%  flow %.2f%%"), state->opacity * 100.0f,
             state->flow * 100.0f);
  g_snprintf(lines[2], sizeof(lines[2]), _("pressure %.2f%%  tilt %.2f%%  acceleration %.2f%%"),
             state->pressure * 100.0f, state->tilt * 100.0f, state->acceleration * 100.0f);
 
  const double pad = DT_PIXEL_APPLY_DPI(6.0);
  const double line_h = DT_PIXEL_APPLY_DPI(13.0);
  const double fs = DT_PIXEL_APPLY_DPI(12.0);
  double max_w = 0.0;
 
  cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
  cairo_set_font_size(cr, fs);
  for(int i = 0; i < 3; i++)
  {
    cairo_text_extents_t ext = { 0 };
    cairo_text_extents(cr, lines[i], &ext);
    max_w = fmax(max_w, ext.x_advance);
  }
 
  const double box_w = max_w + 2.0 * pad;
  const double box_h = 3.0 * line_h + 2.0 * pad;
  const double x = DT_PIXEL_APPLY_DPI(10.0);
  const double y = DT_PIXEL_APPLY_DPI(10.0);
 
  cairo_save(cr);
  cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 0.55);
  cairo_rectangle(cr, x, y, box_w, box_h);
  cairo_fill(cr);
 
  cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.92);
  for(int i = 0; i < 3; i++)
  {
    cairo_move_to(cr, x + pad, y + pad + (i + 1) * line_h - DT_PIXEL_APPLY_DPI(2.0));
    cairo_show_text(cr, lines[i]);
  }
  cairo_restore(cr);
}
 
void gui_post_expose(dt_iop_module_t *self, cairo_t *cr, int32_t width, int32_t height, int32_t pointerx,
                     int32_t pointery)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev)) return;
 
  cairo_save(cr);
  cairo_set_line_width(cr, 1.0);
  cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.8);
 
  if(g->session.pointer_valid)
  {
    dt_control_pointer_input_t pointer_input = { 0 };
    dt_control_get_pointer_input(&pointer_input);
    const float widget_x = isfinite(pointer_input.x)
                               ? (float)pointer_input.x
                               : ((pointerx >= 0 && pointery >= 0) ? (float)pointerx : -1.0f);
    const float widget_y = isfinite(pointer_input.y)
                               ? (float)pointer_input.y
                               : ((pointerx >= 0 && pointery >= 0) ? (float)pointery : -1.0f);
    if(widget_x < 0.0f || widget_y < 0.0f)
    {
      cairo_restore(cr);
      return;
    }
    drawlayer_hud_brush_state_t hud = { 0 };
    _compute_hud_brush_state(&pointer_input, &hud);
 
    float radius = hud.radius;
    const int brush_mode = _conf_brush_mode();
    const gboolean show_paint_fill = (brush_mode == DT_DRAWLAYER_BRUSH_MODE_PAINT);
 
    float draw_x = widget_x;
    float draw_y = widget_y;
    float lx = 0.0f;
    float ly = 0.0f;
    float widget_radius = radius * dt_dev_get_overlay_scale(self->dev);
    if(dt_drawlayer_widget_to_layer_coords(self, widget_x, widget_y, &lx, &ly))
    {
      dt_drawlayer_brush_dab_t dab = {
        .x = lx,
        .y = ly,
        .radius = radius,
      };
      if(!_layer_to_widget_coords(self, lx, ly, &draw_x, &draw_y))
      {
        draw_x = widget_x;
        draw_y = widget_y;
      }
      widget_radius = dt_drawlayer_widget_brush_radius(self, &dab, widget_radius);
    }
 
    // Draw the brush mipmap
    const float draw_radius = fmaxf(0.5f, widget_radius);
    if(show_paint_fill)
    {
      _ensure_cursor_stamp_surface(self, draw_radius, hud.opacity, hud.hardness);
      if(g->ui.cursor_surface)
      {
        const float surface_half_extent = 0.5f * (float)g->ui.cursor_surface_size / (float)g->ui.cursor_surface_ppd;
        cairo_set_source_surface(cr, g->ui.cursor_surface, draw_x - surface_half_extent, draw_y - surface_half_extent);
        cairo_paint(cr);
      }
    }
 
    // Draw the outer circle in case we are lost
    cairo_set_source_rgba(cr, 0., 0., 0., 0.5);
    cairo_set_line_width(cr, 2.5);
    cairo_arc(cr, draw_x, draw_y, draw_radius + 1.0f, 0.0, 2.0 * M_PI);
    cairo_stroke(cr);
 
    cairo_set_source_rgba(cr, 1., 1., 1., 0.5);
    cairo_set_line_width(cr, 1.0);
    cairo_arc(cr, draw_x, draw_y, draw_radius, 0.0, 2.0 * M_PI);
    cairo_stroke(cr);
 
    if(self->dev->gui_module == self)
    {
      _draw_brush_hud(cr, &hud);
    }
  }
 
  cairo_restore(cr);
}
 
int mouse_leave(dt_iop_module_t *self)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g)) return 0;
  drawlayer_runtime_host_context_t runtime_host = {
    .runtime = {
      .self = self,
      .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
      .gui = g,
      .manager = &g->manager,
      .process_state = &g->process,
    },
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = &runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  const dt_drawlayer_runtime_update_request_t update = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_MOUSE_LEAVE,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
  };
  dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  return 0;
}
 
int mouse_moved(dt_iop_module_t *self, double x, double y, double pressure, int which)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev)) return 0;
 
  if(self->request_color_pick != DT_REQUEST_COLORPICK_OFF)
  {
    /* When the standard image color picker is active, drawlayer must stop
     * capturing the pointer entirely so darkroom can drive the picker overlay
     * and sampling path without competing cursor state from the brush tool. */
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t leave_update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_MOUSE_LEAVE,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_STROKE_ABORT,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    if(g->session.pointer_valid) dt_drawlayer_runtime_manager_update(&g->manager, &leave_update, &runtime_manager);
    dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
    return 0;
  }
 
  if(!g->session.pointer_valid)
  {
    drawlayer_runtime_host_context_t enter_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t enter_manager = {
      .user_data = &enter_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    dt_drawlayer_runtime_manager_update(
        &g->manager,
        &(dt_drawlayer_runtime_update_request_t){
          .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_MOUSE_ENTER,
          .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
        },
        &enter_manager);
  }
 
  if(g->manager.painting_active)
  {
    dt_drawlayer_paint_raw_input_t input = { 0 };
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
      .raw_input = &input,
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RAW_INPUT,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_SAMPLE,
    };
    const dt_drawlayer_runtime_result_t dispatch
        = _build_raw_input_event(self, x, y, pressure, DT_DRAWLAYER_PAINT_STROKE_MIDDLE, &input)
              ? dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager)
              : (dt_drawlayer_runtime_result_t){ .ok = FALSE, .raw_input_ok = FALSE };
    if(!dispatch.ok || !dispatch.raw_input_ok)
    {
      /* Queue overflow or enqueue failure aborts the current stroke so GUI and
       * worker stay in sync on stroke boundaries. */
      dt_print(DT_DEBUG_PERF, "[drawlayer] stroke abort from mouse_moved: dispatch.ok=%d raw_input_ok=%d\n",
               dispatch.ok, dispatch.raw_input_ok);
      dt_drawlayer_runtime_manager_update(
          &g->manager,
          &(dt_drawlayer_runtime_update_request_t){
            .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_STROKE_ABORT,
            .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
          },
          &runtime_manager);
    }
  }
  else
  {
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RAW_INPUT,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_SAMPLE,
    };
    dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  }
 
  gtk_widget_queue_draw(dt_gui_center_widget());
  return g->manager.painting_active ? 1 : 0;
}
 
int button_pressed(dt_iop_module_t *self, double x, double y, double pressure, int which, int type, uint32_t state)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  dt_iop_drawlayer_params_t *params = (dt_iop_drawlayer_params_t *)self->params;
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev) || which != 1) return 0;
  if(!_layer_name_non_empty(params ? params->layer_name : NULL)) return 0;
 
  if(self->dev->gui_module != self)
  {
    dt_iop_request_focus(self);
    return 1;
  }
 
  dt_control_pointer_input_t pointer_input = { 0 };
  dt_control_get_pointer_input(&pointer_input);
  const float input_wx = isfinite(pointer_input.x) ? (float)pointer_input.x : (float)x;
  const float input_wy = isfinite(pointer_input.y) ? (float)pointer_input.y : (float)y;
  const float pressure_norm = pointer_input.has_pressure ? _clamp01(pointer_input.pressure) : _clamp01(pressure);
  uint32_t stroke_batch = g->stroke.current_stroke_batch + 1u;
  if(stroke_batch == 0u) stroke_batch++;
  dt_drawlayer_paint_raw_input_t first = {
    .wx = input_wx,
    .wy = input_wy,
    .pressure = pressure_norm,
    .tilt = (float)_clamp01(pointer_input.tilt),
    .acceleration = (float)_clamp01(pointer_input.acceleration),
    .event_ts = g_get_monotonic_time(),
    .stroke_batch = stroke_batch,
    .event_index = 1u,
    .stroke_pos = DT_DRAWLAYER_PAINT_STROKE_FIRST,
  };
  _fill_input_layer_coords(self, &first);
  _fill_input_brush_settings(self, &first);
  drawlayer_runtime_host_context_t runtime_host = {
    .runtime = {
      .self = self,
      .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
      .gui = g,
      .manager = &g->manager,
      .process_state = &g->process,
    },
    .raw_input = &first,
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = &runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  const dt_drawlayer_runtime_update_request_t update = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RAW_INPUT,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_STROKE_BEGIN,
  };
  const dt_drawlayer_runtime_result_t dispatch
      = dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  if(!dispatch.ok)
    return 0;
  if(!dispatch.raw_input_ok)
    dt_control_log(_("failed to queue live drawing stroke"));
  dt_control_mouse_is_painting(TRUE);
  dt_control_queue_redraw_center();
  return 1;
}
 
int button_released(dt_iop_module_t *self, double x, double y, int which, uint32_t state)
{
  dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  if(IS_NULL_PTR(g) || IS_NULL_PTR(self->dev) || which != 1) return 0;
 
  if(g->manager.painting_active)
  {
    dt_control_pointer_input_t pointer_input = { 0 };
    dt_control_get_pointer_input(&pointer_input);
    const float input_wx = isfinite(pointer_input.x) ? (float)pointer_input.x : (float)x;
    const float input_wy = isfinite(pointer_input.y) ? (float)pointer_input.y : (float)y;
    dt_drawlayer_paint_raw_input_t end = {
      .wx = input_wx,
      .wy = input_wy,
      .pressure = pointer_input.has_pressure ? _clamp01(pointer_input.pressure) : 1.0f,
      .tilt = (float)_clamp01(pointer_input.tilt),
      .acceleration = (float)_clamp01(pointer_input.acceleration),
      .event_ts = g_get_monotonic_time(),
      .stroke_batch = g->stroke.current_stroke_batch,
      .event_index = ++g->stroke.stroke_event_index,
      .stroke_pos = DT_DRAWLAYER_PAINT_STROKE_END,
    };
    _fill_input_layer_coords(self, &end);
    _fill_input_brush_settings(self, &end);
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
      .raw_input = &end,
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_RAW_INPUT,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_STROKE_END,
    };
    const dt_drawlayer_runtime_result_t dispatch
        = dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
    if(!dispatch.ok || !dispatch.raw_input_ok)
      dt_control_log(_("failed to queue drawing stroke end"));
    dt_control_queue_redraw_center();
    return 1;
  }
 
  return 0;
}
 
int scrolled(dt_iop_module_t *self, double x, double y, int up, uint32_t state)
{
  if(IS_NULL_PTR(self->dev) || self->dev->gui_module != self) return 0;
 
  // A drawn blend mask being edited (this module's own blending options, not its own painting
  // state below, which never goes through dev->forms) must not leak scroll into the brush-size
  // change here.
  if(self->dev->form_gui && dt_masks_get_visible_form(self->dev)) return 0;
 
  const gboolean increase = dt_mask_scroll_increases(up);
  const float factor = increase ? 1.1f : 0.9f;
  const float new_size = CLAMP(_conf_size() * factor, 1.0f, 2048.0f);
  dt_conf_set_float(DRAWLAYER_CONF_SIZE, new_size);
 
  if(dt_iop_gui_data(self))
  {
    dt_iop_drawlayer_gui_data_t *g = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
    dt_bauhaus_slider_set(g->controls.size, new_size);
    drawlayer_runtime_host_context_t runtime_host = {
      .runtime = {
        .self = self,
        .runtime_params = (const dt_iop_drawlayer_params_t *)self->params,
        .gui = g,
        .manager = &g->manager,
        .process_state = &g->process,
      },
    };
    const dt_drawlayer_runtime_host_t runtime_manager = {
      .user_data = &runtime_host,
      .collect_inputs = _drawlayer_runtime_collect_inputs,
      .perform_action = _drawlayer_runtime_perform_action,
    };
    const dt_drawlayer_runtime_update_request_t update = {
      .event = DT_DRAWLAYER_RUNTIME_EVENT_GUI_SCROLL,
      .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
    };
    dt_drawlayer_runtime_manager_update(&g->manager, &update, &runtime_manager);
  }
  return 1;
}
 
#ifdef HAVE_OPENCL
int process_cl(struct dt_iop_module_t *self, const dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece, cl_mem dev_in, cl_mem dev_out)
{
  const dt_iop_roi_t *const roi_in = &piece->roi_in;
  const dt_iop_roi_t *const roi_out = &piece->roi_out;
  const gint64 process_t0 = g_get_monotonic_time();
  const dt_iop_drawlayer_global_data_t *global = (const dt_iop_drawlayer_global_data_t *)self->global_data;
  dt_iop_drawlayer_gui_data_t *gui = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  const gboolean have_gui = (!IS_NULL_PTR(gui));
  {
    const gboolean display_pipe = have_gui && (pipe == self->dev->pipe || pipe == self->dev->preview_pipe);
    dt_iop_drawlayer_data_t *data = (dt_iop_drawlayer_data_t *)piece->data;
    dt_drawlayer_runtime_manager_bind_piece(&data->headless_manager, &data->process, gui ? &gui->manager : NULL,
                                            gui ? &gui->process : NULL, display_pipe, &data->runtime_manager,
                                            &data->runtime_process, &data->runtime_display_pipe);
  }
  dt_iop_drawlayer_data_t *runtime_data = (dt_iop_drawlayer_data_t *)piece->data;
  const dt_iop_drawlayer_params_t *runtime_params
      = &runtime_data->params;
  if(runtime_params->layer_name[0] != '\0')
    _refresh_piece_base_cache(self, runtime_data, runtime_params, (dt_dev_pixelpipe_t *)pipe,
                              (dt_dev_pixelpipe_iop_t *)piece);
  const drawlayer_runtime_request_t runtime_request = {
    .self = self,
    .pipe = pipe,
    .piece = (dt_dev_pixelpipe_iop_t *)piece,
    .runtime_params = runtime_params,
    .gui = gui,
    .manager = runtime_data->runtime_manager,
    .process_state = runtime_data->runtime_process,
    .display_pipe = runtime_data->runtime_display_pipe,
    .roi_in = roi_in,
    .roi_out = roi_out,
    .use_opencl = TRUE,
  };
  drawlayer_runtime_host_context_t runtime_host = {
    .runtime = runtime_request,
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = &runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  const dt_drawlayer_runtime_update_request_t process_pre = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_PROCESS_CL_BEFORE,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
  };
  dt_drawlayer_runtime_update_request_t process_post = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_PROCESS_CL_AFTER,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
  };
  dt_drawlayer_runtime_manager_t *const manager = runtime_request.manager;
  dt_drawlayer_runtime_manager_update(manager, &process_pre, &runtime_manager);
  if(IS_NULL_PTR(global) || global->kernel_premult_over < 0)
  {
    dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
    return FALSE;
  }
  gboolean fallback = (runtime_params->layer_name[0] == '\0');
 
  const drawlayer_preview_background_t preview_bg = _resolve_preview_background(self, gui);
  drawlayer_process_scratch_t *scratch = _get_process_scratch();
  if(IS_NULL_PTR(scratch))
  {
    dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
    return FALSE;
  }
 
  dt_drawlayer_runtime_source_t source = { 0 };
  if(!fallback) fallback = !_update_runtime_state(&runtime_request, &source);
  if(!fallback)
  {
    const gboolean realtime = dt_dev_pixelpipe_get_realtime(pipe);
    const gboolean reuse_device_buffers = realtime;
    dt_iop_roi_t target_roi = source.target_roi;
    dt_iop_roi_t source_roi = source.source_roi;
    int source_width = source.width;
    int source_height = source.height;
    gboolean direct_copy = source.direct_copy;
    const float *source_pixels = source.pixels;
    dt_pixel_cache_entry_t *source_entry = source.cache_entry;
 
    if(fallback)
      goto process_cl_fallback;
 
    /* The realtime output cacheline is reused in place while only the layer host
     * pixels change, so when the same device buffer comes back for the same layer
     * and geometry it still holds the previous full composite and only the painted
     * sub-rect needs refreshing. The node's global_hash is NOT stable across a
     * stroke (the heartbeat bumps stroke_commit_hash every frame), so we key on
     * the stable base-patch layer identity instead. Validate here; the blend
     * records the new state on success. */
    dt_drawlayer_process_state_t *const pstate = runtime_request.process_state;
    const uint64_t layer_hash = pstate ? pstate->base_patch.cache_hash : 0;
    const gboolean g_valid = pstate && pstate->last_composite_valid;
    const gboolean g_devout = pstate && pstate->last_composite_dev_out == (void *)dev_out;
    const gboolean g_hash = pstate && layer_hash != 0 && pstate->last_composite_layer_hash == layer_hash;
    const gboolean g_roi = pstate && !memcmp(&pstate->last_composite_target_roi, &target_roi, sizeof(dt_iop_roi_t));
    const gboolean allow_partial = realtime && g_valid && g_devout && g_hash && g_roi;
    if(realtime && pstate && !allow_partial && (dt_get_debug_flags() & DT_DEBUG_VERBOSE))
      dt_print(DT_DEBUG_PERF,
               "[drawlayer] partial gate declined: valid=%d devout=%d hash=%d roi=%d\n",
               g_valid, g_devout, g_hash, g_roi);
 
    gboolean ok = _blend_layer_over_input_cl(
        pipe->devid, global->kernel_premult_over, dev_out, dev_in, scratch, source_pixels, source_entry, NULL,
        source_width, source_height, runtime_request.process_state, &target_roi, &source_roi, direct_copy,
        preview_bg.enabled, preview_bg.value,
        reuse_device_buffers, FALSE, allow_partial);
 
    if(pstate)
    {
      if(ok && realtime && !preview_bg.enabled && layer_hash != 0)
      {
        /* dev_out now holds a valid full composite for this layer/geometry,
         * whether produced by the full or the partial path. */
        pstate->last_composite_dev_out = (void *)dev_out;
        pstate->last_composite_layer_hash = layer_hash;
        pstate->last_composite_target_roi = target_roi;
        pstate->last_composite_valid = TRUE;
      }
      else
      {
        pstate->last_composite_valid = FALSE;
        pstate->last_composite_dev_out = NULL;
      }
    }
 
    process_post.release = (dt_drawlayer_runtime_release_t){
      .process = runtime_request.process_state,
      .source = &source,
    };
    if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
      dt_print(DT_DEBUG_PERF, "[drawlayer] process_cl step=blend-base total=%.3f ok=%d\n",
               (g_get_monotonic_time() - process_t0) / 1000.0, ok ? 1 : 0);
    dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
    return ok;
  }
 
process_cl_fallback:
  if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
    dt_print(DT_DEBUG_PERF, "[drawlayer] process_cl step=no-cache-pass-through total=%.3f\n",
             (g_get_monotonic_time() - process_t0) / 1000.0);
  const gboolean ok = dt_iop_clip_and_zoom_roi_cl(pipe->devid, dev_out, dev_in, roi_out, roi_in)
                      == CL_SUCCESS;
  dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
  return ok;
}
#endif
 
__DT_CLONE_TARGETS__
int process(dt_iop_module_t *self, const dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece,
            const void *const ivoid, void *const ovoid)
{
  const dt_iop_roi_t *const roi_in = &piece->roi_in;
  const dt_iop_roi_t *const roi_out = &piece->roi_out;
  dt_iop_drawlayer_gui_data_t *gui = (dt_iop_drawlayer_gui_data_t *)dt_iop_gui_data(self);
  const gboolean have_gui = (!IS_NULL_PTR(gui));
  {
    const gboolean display_pipe = have_gui && (pipe == self->dev->pipe || pipe == self->dev->preview_pipe);
    dt_iop_drawlayer_data_t *data = (dt_iop_drawlayer_data_t *)piece->data;
    dt_drawlayer_runtime_manager_bind_piece(&data->headless_manager, &data->process, gui ? &gui->manager : NULL,
                                            gui ? &gui->process : NULL, display_pipe, &data->runtime_manager,
                                            &data->runtime_process, &data->runtime_display_pipe);
  }
  dt_iop_drawlayer_data_t *runtime_data = (dt_iop_drawlayer_data_t *)piece->data;
  const dt_iop_drawlayer_params_t *runtime_params
      = &runtime_data->params;
  if(runtime_params->layer_name[0] != '\0')
    _refresh_piece_base_cache(self, runtime_data, runtime_params, (dt_dev_pixelpipe_t *)pipe,
                              (dt_dev_pixelpipe_iop_t *)piece);
  const drawlayer_runtime_request_t runtime_request = {
    .self = self,
    .pipe = pipe,
    .piece = (dt_dev_pixelpipe_iop_t *)piece,
    .runtime_params = runtime_params,
    .gui = gui,
    .manager = runtime_data->runtime_manager,
    .process_state = runtime_data->runtime_process,
    .display_pipe = runtime_data->runtime_display_pipe,
    .roi_in = roi_in,
    .roi_out = roi_out,
    .use_opencl = FALSE,
  };
  drawlayer_runtime_host_context_t runtime_host = {
    .runtime = runtime_request,
  };
  const dt_drawlayer_runtime_host_t runtime_manager = {
    .user_data = &runtime_host,
    .collect_inputs = _drawlayer_runtime_collect_inputs,
    .perform_action = _drawlayer_runtime_perform_action,
  };
  const dt_drawlayer_runtime_update_request_t process_pre = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_PROCESS_CPU_BEFORE,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
  };
  dt_drawlayer_runtime_update_request_t process_post = {
    .event = DT_DRAWLAYER_RUNTIME_EVENT_PROCESS_CPU_AFTER,
    .raw_input_kind = DT_DRAWLAYER_RUNTIME_RAW_INPUT_NONE,
  };
  const float *input = (const float *)ivoid;
  float *output = (float *)ovoid;
  const size_t pixels = (size_t)roi_out->width * roi_out->height;
  const gint64 process_t0 = g_get_monotonic_time();
  dt_drawlayer_runtime_manager_t *const manager = runtime_request.manager;
  dt_drawlayer_runtime_manager_update(manager, &process_pre, &runtime_manager);
 
  /* `process()` keeps the pipeline contract simple:
   * - the in-memory cache and stroke math stay in float32,
   * - TIFF I/O converts to/from half-float only at the file boundary. */
  gboolean fallback = (runtime_params->layer_name[0] == '\0');
  const drawlayer_preview_background_t preview_bg = _resolve_preview_background(self, gui);
 
  dt_drawlayer_runtime_source_t source = { 0 };
  if(!fallback) fallback = !_update_runtime_state(&runtime_request, &source);
  if(!fallback)
  {
    const float *layer_pixels = source.pixels;
    if(!source.direct_copy)
    {
      drawlayer_process_scratch_t *scratch = _get_process_scratch();
      if(IS_NULL_PTR(scratch)) fallback = TRUE;
 
      float *layerbuf = NULL;
      if(!fallback)
        layerbuf = dt_drawlayer_cache_ensure_scratch_buffer(&scratch->layerbuf, &scratch->layerbuf_pixels, pixels,
                                                            "drawlayer process scratch");
      if(!fallback && IS_NULL_PTR(layerbuf)) fallback = TRUE;
      if(fallback)
      {
        process_post.release = (dt_drawlayer_runtime_release_t){
          .process = runtime_request.process_state,
          .source = &source,
        };
        goto fallback_pass_through;
      }
      /* Bilinear (not the user pref) for the layer matte — see the OpenCL path in
       * _drawlayer_copy_or_resample_layer_roi: no negative lobes => no overshoot,
       * so no edge halos / out-of-range premultiplied alpha. */
      {
        const struct dt_interpolation *const itor = dt_interpolation_new(DT_INTERPOLATION_BILINEAR);
        dt_interpolation_resample(itor, layerbuf, &source.target_roi, source.pixels, &source.source_roi);
      }
      layer_pixels = layerbuf;
    }
 
    _blend_layer_over_input(output, input, layer_pixels, pixels, preview_bg.enabled, preview_bg.value);
    if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
      dt_print(DT_DEBUG_PERF, "[drawlayer] process step=blend-base total=%.3f\n",
               (g_get_monotonic_time() - process_t0) / 1000.0);
 
    process_post.release = (dt_drawlayer_runtime_release_t){
      .process = runtime_request.process_state,
      .source = &source,
    };
    dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
    return 0;
  }
 
  /* The sidecar is intentionally managed outside of `process()`. Once a layer
   * is loaded, the in-memory caches are authoritative until module-level flush
   * points write them back. If we do not have a usable in-memory cache here,
   * the correct backend behavior is therefore a no-op pass-through rather than
   * reopening/scanning/loading the TIFF in the hot process path. */
fallback_pass_through:
  if(dt_get_debug_flags() & DT_DEBUG_VERBOSE)
    dt_print(DT_DEBUG_PERF, "[drawlayer] process step=no-cache-pass-through total=%.3f\n",
             (g_get_monotonic_time() - process_t0) / 1000.0);
  dt_iop_image_copy_by_size(output, input, roi_out->width, roi_out->height, 4);
  dt_drawlayer_runtime_manager_update(manager, &process_post, &runtime_manager);
  return 0;
}